Lawmakers, federal regulators and thrift industry representatives disagreed yesterday over a rule designed to give federal agencies more authority to monitor some of the state-chartered thrift institutions they insure.

Congress would be making a "fundamental mistake" if it blocked implementation of a rule that increases federal supervision of direct investments by some state-chartered thrift institutions, Federal Home Loan Bank Board Chairman Edwin J. Gray said yesterday.

Gray defended the FHLBB's new rule at a hearing held by a House banking, finance and urban affairs subcommittee.

The rule, which took effect March 18, gives the FHLBB the authority to review certain direct investments by state-chartered, federally insured savings and loan institutions.

Direct investments, as opposed to traditional debt investment, include investments in real estate, business ventures and other areas that were out of bounds to thrifts before deregulation.

Such investments can be more profitable -- and more risky -- than traditional thrift investments. Concern about the risk to the Federal Savings and Loan Insurance Corp. has sparked debate about whether some reregulation is needed to protect its insurance fund.

Rep. Frank Annunzio (D-Ill.), with the support of 223 co-sponsors, has introduced a resolution that would require the FHLBB to delay enforcing the rule until June 30.

The new rule addresses a "narrow aspect" of a bigger problem -- the size and strength of the FSLIC insurance fund -- Annunzio said at the hearing. He urged temporary suspension of the rule to allow debate and possible action to strengthen the fund.

The FHLBB's rule gives its banks the authority to review any direct investment by a state-chartered, federally insured thriftthat exceeds 10 percent of its assets or is twice its net worth.

The purpose of the regulation is to help the bank board "to better underwrite the risk of loss to the FSLIC from direct investment activity," Gray said.

The bank board legally cannot vary FSLIC insurance premiums according to risk, Gray said. A regulatory means of monitoring risk is necessary "unless and until the Congress gives us the right to underwrite risk through a premium payments scheme which assesses higher premiums on those institutions which choose to engage in more risky activities," he said.

The National Council of Savings Institutions called the new rule an "unjustifiable inhibition on the operation of sound, healthy institutions." The council recommends modifying the rule to allow exemptions for savings institutions with "sound net-worth positions," council President Saul B. Klaman said.

The National Association of State Savings & Loan Supervisors said the new rule is an "intrusion on the dual system" of federal and state charters. "Fundamental to this system is the right of each chartering authority to establish the investment powers available to the financial institutions incorporated thereby," said L. L. Bowman III, commissioner of the Texas Savings and Loan Department.

The bank board's rule won the support of the U.S. League of Savings Institutions.