Federal Reserve Chairman Paul A. Volcker yesterday urged Congress to restrict the risky activities of financial institutions now allowed by some states that have produced a "kamikaze attitude" at some thrift institutions seeking high profits.

Volcker told the Senate Banking Committee that restricting activities such as investment in certain types of real estate development is far more urgent than making changes in the system of federal deposit insurance, the subject of the hearing at which he testified.

The Fed chairman argued that even with "a significant increase in actual or near failures" of financial institutions, the current system of supervision and insurance has worked well.

"The points of particular pressure have been dealt with in a manner that has avoided contagious chain reactions, and the health of other financial institutions and the economy has not been undermined," he said.

Both the House and Senate Banking committees have been wrestling with the issue of whether and how to restrict some of the state-sanctioned activities to which Volcker referred, but so far neither has been able to reach a consensus.

The legislators are reluctant to set such limits and anger state authorities and the institutions that have been taking advantage of the newly allowed activities.

Even in the case of the so-called South Dakota loophole, in which that state allows banks based there to engage in certain activities so long as they only do so outside South Dakota, the committees have not moved, despite repeated pleas from the Fed chairman that they do so.

At yesterday's hearing, Volcker also indicated he would not favor two proposals for changing the deposit insurance system: charging higher insurance premiums at institutions that make riskier loans and investments and reducing the maximum amount of money in a single account that would be covered by insurance from the present $100,000.

In many cases, it would be extremely difficult to identify risky loan and investment areas in advance, he said.

Loans in the energy, shipping, agricultural and real estate areas have turned out to be risky in a period of transition from high inflation to lower inflation, he said, but that could not necessarily be determined in advance.

"If differential insurance premiums are to effectively deter excessive risk-taking, the range between premiums charged institutions exposed to relatively great risk and those operating more conservatively would have to be fairly wide," Volcker said.

"But such a wide range for premiums implies more precision in gauging the risk exposure of different institutions or different types of lending than may be objectively possible, or that is widely perceived as fair.

"We don't, for instance, want to indiscriminately place a drag on commercial lending, or agricultural lending, or energy lending," he continued.

"The size of the insurance premiums might be interpreted as a kind of credit rating, but it would be too crude to bear that burden. And I don't see, in practice, how the premiums could be 'fine-tuned' before problems in fact emerge."

As for the other proposal, Volcker said, "It seems likely that if insurance coverage were reduced somewhat, the main effect would be that most smaller depositors with amounts to place that exceed the cutoff would simply channel them into two or more deposit accounts with different institutions."

The Fed chairman also took a dim view of a suggestion by William Isaac, chairman of the Federal Deposit Insurance Corp., which insures deposits at commercial and savings banks, that the Federal Reserve should lend money to institutions that are in trouble without requiring that the loans be secured by good assets.

Isaac complained earlier this year that by lending only on a secured basis, the Fed sometimes ties up all of an institution's good assets and makes a run on it more likely.