EX-99. CERT

                      CERTIFICATION PURSUANT TO SECTION 302
                        OF THE SARBANES-OXLEY ACT OF 2002

- --------------------------------------------------------------------------------

I, Terry K. Glenn, President of WCMA Government Securities Fund and Master
Government Securities Trust, certify that:

1.    I have reviewed this report on Form N-CSR of WCMA Government Securities
      Fund and Master Government Securities Trust (together, the "Fund");

2.    Based on my knowledge, this report does not contain any untrue statement
      of a material fact or omit to state a material fact necessary to make the
      statements made, in light of the circumstances under which such statements
      were made, not misleading with respect to the period covered by this
      report; and

3.    Based on my knowledge, the financial statements, and other financial
      information included in this report, fairly present in all material
      respects the financial condition, results of operations, changes in net
      assets, and cash flows (if the financial statements are required to
      include a statement of cash flows) of the Fund as of, and for, the periods
      presented in this report;

4.    The Fund's other certifying officers and I are responsible for
      establishing and maintaining disclosure controls and procedures (as
      defined in Rule 30a-3(c) under the Investment Company Act of 1940) for the
      Fund and have:

      a)    designed such disclosure controls and procedures, or caused such
            disclosure controls and procedures to be designed under our
            supervision, to ensure that material information relating to the
            Fund, including its consolidated subsidiaries, is made known to us
            by others within those entities, particularly during the period in
            which this report is being prepared;

      b)    evaluated the effectiveness of the Fund's disclosure controls and
            procedures and presented in this report our conclusions about the
            effectiveness of the disclosure controls and procedures, as of a
            date within 90 days prior to the filing date of this report based on
            such evaluation; and



      c)    disclosed in this report any change in the Fund's internal control
            over financial reporting that occurred during the Fund's most recent
            fiscal half-year (the Fund's second fiscal half-year in the case of
            an annual report) that has materially affected, or is reasonably
            likely to materially affect, the Fund's internal control over
            financial reporting; and

5.    The Fund's other certifying officer(s) and I have disclosed, based on our
      most recent evaluation, to the Fund's auditors and the audit committee of
      the Fund's board of directors (or persons performing the equivalent
      functions):

      a)    all significant deficiencies and material weaknesses in the design
            or operation of internal control over financial reporting which are
            reasonably likely to adversely affect the Fund's ability to record,
            process, summarize, and report financial information; and

      b)    any fraud, whether or not material, that involves management or
            other employees who have a significant role in the Fund's internal
            control over financial reporting.

      Date: November 21, 2003


                                         /s/ Terry K. Glenn
                                         ------------------
                                         Terry K. Glenn,
                                         President of WCMA Government Securities
                                         Fund and Master Government Securities
                                         Trust


EX-99. CERT

                      CERTIFICATION PURSUANT TO SECTION 302
                        OF THE SARBANES-OXLEY ACT OF 2002

- --------------------------------------------------------------------------------

I, Donald C. Burke, Chief Financial Officer of WCMA Government Securities Fund
and Master Government Securities Trust, certify that:

1.    I have reviewed this report on Form N-CSR of WCMA Government Securities
      Fund and Master Government Securities Trust (together, the "Fund");

2.    Based on my knowledge, this report does not contain any untrue statement
      of a material fact or omit to state a material fact necessary to make the
      statements made, in light of the circumstances under which such statements
      were made, not misleading with respect to the period covered by this
      report;

3.    Based on my knowledge, the financial statements, and other financial
      information included in this report, fairly present in all material
      respects the financial condition, results of operations, changes in net
      assets, and cash flows (if the financial statements are required to
      include a statement of cash flows) of the Fund as of, and for, the periods
      presented in this report;

4.    The Fund's other certifying officers and I are responsible for
      establishing and maintaining disclosure controls and procedures (as
      defined in Rule 30a-3(c) under the Investment Company Act of 1940) for the
      Fund and have:

      a)    designed such disclosure controls and procedures, or caused such
            disclosure controls and procedures to be designed under our
            supervision, to ensure that material information relating to the
            Fund, including its consolidated subsidiaries, is made known to us
            by others within those entities, particularly during the period in
            which this report is being prepared;

      b)    evaluated the effectiveness of the Fund's disclosure controls and
            procedures and presented in this report our conclusions about the
            effectiveness of the disclosure controls and procedures, as of a
            date within 90 days prior to the filing date of this report based on
            such evaluation; and



      c)    disclosed in this report any change in the Fund's internal control
            over financial reporting that occurred during the Fund's most recent
            fiscal half-year (the Fund's second fiscal half-year in the case of
            an annual report) that has materially affected, or is reasonably
            likely to materially affect, the Fund's internal control over
            financial reporting; and

5.    The Fund's other certifying officer(s) and I have disclosed, based on our
      most recent evaluation, to the Fund's auditors and the audit committee of
      the Fund's board of directors (or persons performing the equivalent
      functions):

      a)    all significant deficiencies and material weaknesses in the design
            or operation of internal control over financial reporting which are
            reasonably likely to adversely affect the Fund's ability to record,
            process, summarize, and report financial information; and

      b)    any fraud, whether or not material, that involves management or
            other employees who have a significant role in the Fund's internal
            control over financial reporting.

      Date: November 21, 2003


                                             /s/ Donald C. Burke
                                             -------------------
                                             Donald C. Burke,
                                             Chief Financial Officer of
                                             WCMA Government Securities Fund and
                                             Master Government Securities Trust