Federal deposit insurance, set up 54 years ago to restore confidence in the nation's banking institutions after the Great Depression, is one of the contributors to today's epidemic of failures, according to a growing number of regulators and experts.

Although scarcely a word about the problem has been heard from presidential contenders Michael S. Dukakis or George Bush, it may well become a consumer issue this winter. Congress will discuss not only a publicly financed rescue of the thrift insurance fund - which could lead to an eventual tax increase - but also reform proposals that include lowering the cap on insured deposits.The Federal Deposit Insurance Corp., which insures deposits in commercial banks, has been re-examining the deposit insurance system and will unveil its study late next month. And a number of legislators and consultants already have their own proposals for revamping the system, which has remained basically unchanged since it was created in the aftermath of the banking panics of the 1930s.

The catalyst for the re-examination of the insurance system is the severe hemorrhaging of savings and loans, which had lost $7.5 billion by mid-1988. Most of the losses occurred in states hit hard by recessions in the oil and agricultural sectors.

Trying to deal with a mounting caseload of hundreds of insolvent thrifts has drained the coffers of the Federal Savings and Loan Insurance Corp., which guarantees thrift deposits. The FDIC is better off, but its reserves are dropping.

Top officials at both insurance funds say deposit insurance reform probably has to be an essential ingredient of any long-term solution.

"The structure of deposit insurance is at the heart of the question," said Lawrence White, one of three members of the Federal Home Loan Bank Board, which oversees the thrift insurance fund.

M. Danny Wall, the bank board's chairman, thinks one problem is the size of the premiums that thrifts and banks pay to support the insurance funds. Set by Congress at one-twelfth of 1 percent of an institution's deposits in the 1930s, they have changed only once, when an additional premium of one-eighth of 1 percent was levied on thrifts in 1985 as a result of the industry's problems. Congress never intended those premiums to deal with "the abnormal and catastrophic losses that are occurring" in the 1980s, Wall said.

Others, however, put most of the onus for the FSLIC's and the FDIC's difficulties on the insurance contract itself, which they say has encouraged bad lending practices by banks and thrifts. That's because if deposits are insured up to $100,000, people don't worry about an institution's financial health when they decide where to put their money, experts say. Banks and thrifts therefore are free to make risky investments without wondering whether they will lose deposits as a result.

Critics also say that by boosting the maximum insured deposit to $100,000 in 1980 - its level since 1969 had been $40,000 - Congress encouraged the growth of brokered deposits, which flow from institution to institution depending on where they can earn the highest interest rate. Those large deposits have increased the burden on the insurance funds and led to rate wars among thrifts. And the institutions have had even more of an incentive to make risky loans in order to try to cover their high deposit costs. "For the first time," said Bert Ely, a deposit insurance specialist, "we're seeing a government-run Ponzi scheme."

Amid growing publicity about the cost of a solution, estimated at $50 billion to $100 billion for the thrift insurance fund alone, politicians have tried to stay away from the issue.

One reason is that they're afraid of causing bank runs. Another is that Republicans and Democrats alike can be held responsible for the situation, according to Edward J. Kane, a finance professor at Ohio State University and an authority on regulation.

A number of suggestions for reform have surfaced, and all are likely to be considered after the election. One is for a rollback in the amount of a deposit that insurance will cover, in hopes of not only reducing the obligations of the insurance funds, but also of discouraging deposits in weak institutions. Supporters call the concept "market discipline."

Rep. James Leach, R-Iowa, a senior member of the House Banking Committee, said he would bring up for consideration next year a cap of $20,000 on insured deposits in institutions that aren't well capitalized. "That forces a person putting in deposits to look at the strength of an institution," Leach said.

The idea of an insurance rollback is supported by a sizable number of experts, including R. Dan Brumbaugh, a former deputy chief economist with the Federal Home Loan Bank Board. Others, however, consider a lowered cap a dangerous concept because they believe it increases the possibility of runs.