House-Senate conferees last night approved several last-minute changes in a major civil rights bill in an attempt to improve its chances of enactment, with or without a veto by President Bush.

The bill's supporters said the modifications, which generally would give employers more latitude in defending against discrimination suits, could produce enough votes to override a presidential veto. They also expressed hope that the threat of an override might help convince the president to sign the bill.

The legislation, which would overturn six recent Supreme Court decisions that made it harder for workers to sue their employers for discrimination, is expected to go to the Senate and House floors next week for final approval.

The White House has said the president will veto the measure on grounds it could force employers to impose hiring and promotion quotas based on race and sex in order to avoid costly lawsuits, a contention denied by the bill's supporters.

In an attempt to work out a compromise with the Bush administration, Sen. Orrin G. Hatch (R-Utah), who led the fight against the measure in the Senate, joined other Republican senators in intensive behind-the-scenes negotiations with civil rights groups and administration officials over the past few weeks.

Hatch indicated a seven-point compromise worked out during the talks was "acceptable to him although not perfect," and recommended that the administration accept it, Sen. Arlen Specter (R-Pa.), a supporter of the legislation and key figure in the negotiations, told the conferees.

But administration officials, later identified as Attorney General Dick Thornburgh and White House counsel C. Boyden Gray, did not approve the plan, according to Specter and Hatch. Because Hatch's goal had been to seek a compromise among all the parties, he did not support the final version of the conference agreement.

A Senate proposal incorporating the seven points was approved by the House conferees on a vote of 11 to 8, largely along party lines. One black lawmaker, Rep. Craig Washington (D-Tex.), voted against the changed version of the bill, saying the modifications turned the legislation into "the hollow shell of a civil rights bill." Other black conferees voted for it.

Both houses earlier approved their own versions of the legislation by margins that fell just short of the two-thirds votes needed to override a veto: 12 votes in the House and two in the Senate.

Sen. Edward M. Kennedy (D-Mass.), chief sponsor of the Senate bill, said after the brief conference session that he believed the bill would now pick up enough votes to override a veto. He also indicated he had not given up hope the president would sign it.

Specter also said he thought it was a "distinct possibility" that a veto could be overridden, although the outcome could depend on a number of factors, including the intensity of an administration lobbying campaign against an override.

The central problem remained the quota question, Specter said. In a key revision, the Senate negotiators proposed that workers complaining that hiring or promotion practices had a "disparate impact" on minorities and women would have to prove that a "specific practice or practices" was responsible for it.

While this satisfied some lawmakers concerned about quotas, the administration apparently did not feel it went far enough to protect employers from imposing quotas to fend off lawsuits, Specter said.