------------------------------
                               UNITED STATES                                OMB APPROVAL
                    SECURITIES AND EXCHANGE COMMISSION             ------------------------------
                          Washington, D.C. 20549                   OMB Number 3235-0145
                                                                   ------------------------------
                                                                   Expires:   January 31, 2006
                                                                   ------------------------------
                                                                   Estimated average burden
                                                                   hours per response . . . 11


                              INITIAL SCHEDULE 13G


                    Under the Securities Exchange Act of 1934


                              Modtech Holding, Inc.
-------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
-------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    60783C100
-------------------------------------------------------------------------------
                                 (CUSIP Number)

                                December 31, 2005
-------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

        |x|       Rule 13d-1(b)

                  Rule 13d-1(c)

                  Rule 13d-1(d)


*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).








                                PAGE 1 OF 7 PAGES





----------------------                                    ---------------------
CUSIP No. 60783C100                 13G                   Page  2  of  7  Pages
----------------------                                    ---------------------

-------------------------------------------------------------------------------
        
    1      NAME OF REPORTING PERSON
           I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only).

           Manulife Financial Corporation

-------------------------------------------------------------------------------
    2      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*      (a)  |_|
                                                                  (b)  |_|
           N/A
-------------------------------------------------------------------------------
    3      SEC USE ONLY

-------------------------------------------------------------------------------
    4      CITIZENSHIP OR PLACE OF ORGANIZATION

           Canada

-------------------------------------------------------------------------------
                       5     SOLE VOTING POWER

                             -0-
                       --------------------------------------------------------
    Number of          6     SHARED VOTING POWER
      Shares
   Beneficially              -0-
     Owned by          --------------------------------------------------------
       Each            7     SOLE DISPOSITIVE POWER
    Reporting
      Person                 -0-
       With            --------------------------------------------------------
                       8     SHARED DISPOSITIVE POWER

                             -0-
-------------------------------------------------------------------------------
    9      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           None,  except through its indirect,  wholly-owned  subsidiary,  John
           Hancock Advisers, LLC

-------------------------------------------------------------------------------
   10      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           N/A
-------------------------------------------------------------------------------
   11      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

           See line 9, above.
-------------------------------------------------------------------------------
   12      TYPE OF REPORTING PERSON*

           HC
-------------------------------------------------------------------------------

                      *SEE INSTRUCTIONS BEFORE FILLING OUT!
                                PAGE 2 OF 7 PAGES






----------------------                                    ---------------------
CUSIP No. 60783C100                 13G                   Page  3  of  7  Pages
----------------------                                    ---------------------

-------------------------------------------------------------------------------
        
    1      NAME OF REPORTING PERSON
           I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only).

           John Hancock Advisers, LLC

-------------------------------------------------------------------------------
    2      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*      (a)  |_|
                                                                  (b)  |_|
           N/A
-------------------------------------------------------------------------------
    3      SEC USE ONLY

-------------------------------------------------------------------------------
    4      CITIZENSHIP OR PLACE OF ORGANIZATION

           Delaware
-------------------------------------------------------------------------------
                       5     SOLE VOTING POWER

                             904,538
                       --------------------------------------------------------
    Number of          6     SHARED VOTING POWER
      Shares
   Beneficially              -0-
     Owned by          --------------------------------------------------------
       Each            7     SOLE DISPOSITIVE POWER
    Reporting
      Person                 -0-
       With            --------------------------------------------------------
                       8     SHARED DISPOSITIVE POWER

                             904,538
-------------------------------------------------------------------------------
    9      AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

           904,538
-------------------------------------------------------------------------------
   10      CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

           N/A
-------------------------------------------------------------------------------
   11      PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

           5.3%
-------------------------------------------------------------------------------
   12      TYPE OF REPORTING PERSON*

           IA
-------------------------------------------------------------------------------

                      *SEE INSTRUCTIONS BEFORE FILLING OUT!
                                PAGE 3 OF 7 PAGES



Attention:  Intentional  misstatements  or omissions of fact constitute  Federal
            criminal violations (See 18 U.S.C. 1001)

   Item 1(a)    Name of Issuer:
                ---------------
                Modtech Holding, Inc.

   Item 1(b)    Address of Issuer's Principal Executive Offices:
                ------------------------------------------------
                2830 Barrett Avenue
                Perris, CA 92571

   Item 2(a)    Name of Person Filing:
                ----------------------
                This filing is made on behalf of Manulife Financial  Corporation
                ("MFC"),  and  MFC's  indirect,  wholly-owned  subsidiary,  John
                Hancock Advisers LLC ("JHA").

   Item 2(b)    Address of the Principal Offices:
                ---------------------------------
                The  principal  business  office of MFC is  located at 200 Bloor
                Street, East, Toronto,  Ontario,  Canada, M4W 1E5. The principal
                business  office  of JHA is  located  at  601  Congress  Street,
                Boston, Massachusetts 02210.

   Item 2(c)    Citizenship:
                ------------
                MFC is organized and exist under the laws of Canada.
                JHA is  organized  and exists  under  the  laws of the  State of
                Delaware.

   Item 2(d)    Title of Class of Securities:
                -----------------------------
                Common Stock

   Item 2(e)    CUSIP Number:
                -------------
                60783C100

   Item 3       If the Statement is being filed pursuant to Rule 13d-1(b),
                or 13d-2(b), check whether the person filing is a:

                MFC:        (g) (X) Parent Holding Company, in accordance
                                    with ss.240.13d-1(b)(ii)(G).

                JHA:        (e) (X) Investment Adviser registered under
                                    ss.203 of the Investment Advisers Act
                                    of 1940.

   Item 4       Ownership:
                ----------

                (a) Amount Beneficially  Owned: JHA has beneficial  ownership of
                    904,538    shares   of    Common    Stock.    Through    its
                    parent-subsidiary  relationship to JHA, MFC may be deemed to
                    have beneficial ownership of these same shares.

                (b) Percent of Class:
                    Of the 17,054,719 shares  outstanding as of November 1, 2005
                    according to the issuer's  quarterly report on form 10-Q for
                    the period ended  September 30, 2005, JHA held 5.3%.

                (c) Number of shares as to which the person has:

                    (i) sole power to vote or to direct the vote:
                        JHA has sole  power to vote or to direct  the  voting of
                        the shares of Common Stock it beneficially owns.

                                PAGE 4 OF 7 PAGES



                   (ii) shared power to vote or to direct the vote: -0-

                  (iii) sole power to dispose or to direct the disposition of:
                        -0-

                   (iv) shared power to dispose or to direct the disposition of:
                        JHA  has  shared  power  to  dispose  or to  direct  the
                        disposition of the shares it beneficially owns.


   Item 5       Ownership of Five Percent or Less of a Class:
                ---------------------------------------------
                Not applicable.

   Item 6       Ownership of More than Five Percent on Behalf of Another Person:
                ----------------------------------------------------------------
                Not applicable.

   Item 7       Identification and Classification of the Subsidiary which
                Acquired the Security Being Reported on by the Parent
                Holding Company:
                ---------------------------------------------------------
                See Items 3 and 4 above.

   Item 8       Identification and Classification of Members of the Group:
                ----------------------------------------------------------
                Not applicable.

   Item 9       Notice of Dissolution of a Group:
                ---------------------------------
                Not applicable.

   Item 10      Certification:
                --------------
                By signing below the undersigned  certifies that, to the best of
                its knowledge and belief, the securities  referred to above were
                acquired  and are held in the  ordinary  course of business  and
                were not  acquired  and are not held for the  purpose of or with
                the effect of changing or influencing  the control of the issuer
                of the  securities  and  were not  acquired  and are not held in
                connection  with or as a participant in any  transaction  having
                that purpose or effect.

                                PAGE 5 OF 7 PAGES



                                    SIGNATURE

     After reasonable inquiry and to the best of its knowledge and belief,  each
of the undersigned certifies that the information set forth in this statement is
true, complete and correct.

                               Manulife Financial Corporation

                               By:      /s/ Angela Shaffer
                                        ----------------------
                                        Name:   Angela Shaffer
                                        Title:  Vice President and
Dated:  February 8, 2006                        Corporate Secretary


                               John Hancock Advisers, LLC

                               By:      /s/Al Ouellette
                                        ---------------
                                        Name:   Al Ouellette
                                        Title:  Assistant Vice President and
Dated:  February 8, 2006                        Senior Counsel




                                PAGE 6 OF 7 PAGES




EXHIBIT A

                             JOINT FILING AGREEMENT
                             ----------------------

      Manulife Financial  Corporation and John Hancock Advisers,  LLC agree that
the Initial  Schedule 13G, to which this Agreement is attached,  relating to the
Common Stock of Modtech Holding, Inc. is filed on behalf of each of them.


                               Manulife Financial Corporation

                               By:      /s/ Angela Shaffer
                                        ----------------------
                                        Name:   Angela Shaffer
                                        Title:  Vice President and
Dated:  February 8, 2006                        Corporate Secretary


                               John Hancock Advisers, LLC

                               By:      /s/Al Ouellette
                                        ---------------
                                        Name:   Al Ouellette
                                        Title:  Assistant Vice President and
Dated:  February 8, 2006                        Senior Counsel




                                PAGE 7 OF 7 PAGES