NEW YORK, FEB. 13 -- The Internal Revenue Service said today it filed bankruptcy court claims for $5.28 billion against Drexel Burnham Lambert Inc. for allegedly unpaid taxes plus penalties and interest.

The claims seek unpaid income, excise and employment taxes for 1980 through 1990 from the collapsed Wall Street firm, which sought bankruptcy court refuge a year ago today.

Drexel, which is operating under supervision of the federal bankruptcy court, said the claims are exaggerated.

The IRS generally receives the money it is owed from a bankrupt firm before other creditors are paid. It will be up to the courts, however, to determine how much the IRS is really owed by Drexel and what portion of that amount will receive priority status.

In a statement today, Drexel said that some of the IRS claims may have merit, but not all of them. "Drexel's board will vigorously defend against any efforts to unfairly usurp its assets," the company said.

Other government agencies also are seeking billions of dollars from Drexel, which collapsed after pleading guilty to six felonies and agreeing to pay $650 million in fines and restitution. The Federal Deposit Insurance Corp. and Resolution Trust Corp. are seeking $6.8 billion, claiming that Drexel contributed to the failure of more than 40 savings and loans by fraudulent sales of risky, high-yield junk bonds.

Overall, Drexel faces more than $30 billion in claims related to securities law violations it admitted in 1989.