Exhibit 99.1350CERT

         Certification Pursuant to Section 906 of the Sarbanes Oxley Act

I, Terry K. Glenn, President of MuniHoldings New Jersey Insured Fund, Inc. (the
"Fund"), certify that:

      1.    The N-CSR of the Fund (the "Report") fully complies with the
            requirements of Section 13(a) or 15(d) of the Securities Exchange
            Act of 1934; and

      2.    The information contained in the Report fairly presents, in all
            material respects, the financial condition and results of operations
            of the Fund.

Dated: March 17, 2003

                                                /s/ Terry K. Glenn
                                                --------------------------------
                                                Terry K. Glenn,
                                                President of
                                                MuniHoldings New Jersey
                                                Insured Fund, Inc.


Exhibit 99.1350CERT

         Certification Pursuant to Section 906 of the Sarbanes Oxley Act

I, Donald C. Burke, Chief Financial Officer of MuniHoldings New Jersey Insured
Fund, Inc. (the "Fund"), certify that:

      1.    The N-CSR of the Fund (the "Report") fully complies with the
            requirements of Section 13(a) or 15(d) of the Securities Exchange
            Act of 1934; and

      2.    The information contained in the Report fairly presents, in all
            material respects, the financial condition and results of operations
            of the Fund.

Dated: March 17, 2003

                                                /s/ Donald C. Burke
                                                --------------------------------
                                                Donald C. Burke,
                                                Chief Financial Officer of
                                                MuniHoldings New Jersey
                                                Insured Fund, Inc.