In an effort to boost lagging sales of Keogh and Individual Retirement Accounts, federal banking regulators yesterday proposed changing or eliminating present time and interest-ceiling restrictions on them. c

At present IRA/Keogh accounts at banks and thrift institutions total $18 billion, or approximately 3 percent of all small-denomination time deposits. Latest available figures show that just over half of those persons with incomes over $50,000 who are eligible to set up their own retirement plans do so. In the $10,000-$15,000 range, it falls to 3.3 percent.

The Depository Institutions Deregulation Committee put out for public comment five options affecting special three-year IRA/Keogh accounts. They range from reducing the maturity to one year and raising the interest ceiling beyond the current 8 percent to total deregulation. The last option was suggested by Lawrence Connell, chairman of the National Credit Union Administration, who argued it was consistent with the committee's mandate to deregulate. The DIDC has been criticized for creating more regulations than it eliminates.

Treasury Secretary G. William Miller successfully made the same argument in opposition to a proposal by Federal Reserve Chairman Paul Volcker asking the committee to seek a definition of emergencies in which penalties would be waived for premature withdrawal of savings certificate funds. Miller said individual banks should make their own decisions. In the end the DIDC voted to leave existing penalties in force.

In other action, the DIDC worked out a complicated formula for phasing out so-called finders fees over an 18-month period. These fees are paid to persons who get others to make time deposits, but because they usually revert to the depositors, they amount to increased interest. The maximum percentage of maturing finders-fee deposits that could be raised through the use of the fees would be reduced gradually 85 to 60 to 40 percent preceding total elimination.

The panel rejected a petition from the American Bankers Association to reconsider its decision of last September not to allow banks to pay one-quarter percentage point more on their savings accounts than on their 5 1/4 percent NOW checking-with-interest accounts.

Volcker admitted that while he thought the bankers were justified in requesting a differential, he did not know how to solve the issue at the moment. Current law allows thrift institutions to pay one-quarter percentage point more than banks on savings accounts, so the banks' passbook savings rate could not be raised without also raising the thrifts' rate, a move they oppose.

The ABA also had asked the DIDC not to permit federal credit unions to pay more interest on their share draft accounts (the equivalent of NOWs). tA few currently pay up to 7 percent nominal interest. Their trade association, the Credit Union National Association, reminded the DIDC that it has no jurisdiction over them, so the matter was not discussed.

This week the ABA asked the DIDC to allow banks and thrifts to issue new certificates with higher yields and shorter maturities than their six-month money market certificates.