President Bush, vowing a Monday veto of the 1990 Civil Rights Act now on his desk, challenged Congress last night to pass a new White House version opponents said was a step backward that would "gut" the legislation.

After days of turmoil over whether the White House should compromise, Bush sent Congress a handful of wording changes dealing with pivotal issues on employee and employer rights in discrimination cases. With those changes, which have been in dispute for months, "we can produce legislation that will strike a blow against racial bias without institutionalizing quotas," Bush said in a message to Congress.

Ralph Neas, executive director of the Leadership Conference on Civil Rights, said the changes would "gut the civil rights act" and have the opposite effect intended by the law.

Sen. Edward M. Kennedy (D-Mass.), who sponsored the measure, said, "I am concerned that with this proposal, the president is bowing to his anti-civil rights advisers and is moving even further away from the strong measures that are needed to prevent discrimination in the workplace."

The presidential statement came after Bush and his aides engaged in a marathon battle over how much to compromise with supporters of the Civil Rights Act in order to avoid a veto just weeks before elections. Friday night and all day yesterday, Bush's aides drafted and redrafted new language in key provisions of the legislation and debated the results.

By 8 p.m. last night, after a review by Bush, who is at Camp David for the weekend, the White House issued the statement and a transmittal letter to Congress. The proposed new language for the bill was released later.

Among changes, the White House agreed to an $150,000 cap on all damages a victim of discrimination could gain and would allow jury trials only if a court ruled a ban on such trials is unconstitutional. As passed, the bill would allow $150,000 and additional damages for pain and suffering and would mandate jury trials.

On the most contentious issue, the kind of defenses businesses could use against charges of discrimination that all parties agree was unintentional, the White House substituted new language that Neas called worse than its last proposal. White House counsel C. Boyden Gray said last night that civil rights groups "would call anything that we propose a step backwards."

The decision to schedule a veto on Monday is a much more hard-line tactic than the strategy sketched by White House press secretary Marlin Fitzwater Friday. He said then that Bush would avoid a veto for the 10 days he was allowed to keep the legislation without action in order to give Congress time to pass companion legislation that would "correct" the bill before him.

House Speaker Thomas S. Foley (D-Wash.) said he doubted if changes such as those he heard discussed by the White House would cause Congress to reopen the issue. "I doubt very much if any of the suggestions that the president has made, which seem to me to be just a recycling of previous complaints, are going to lead to any reconsideration of the legislation."

Passed by both houses of Congress with large, but not veto-proof, majorities, the bill would nullify six Supreme Court decisions last year that had the effect of making it more difficult for women and minorities to win job discrimination suits.

Bush's senior aides spent weeks before the legislation was adopted trying to negotiate a compromise, enlisting prominent black Republican lawyer William T. Coleman Jr. as a broker between the White House and the bill's supporters.

Even after the legislation was approved, the negotiation attempt went forward. But it essentially collapsed Friday night when White House Chief of Staff John H. Sununu informed several outsiders working on a possible deal that the White House thought further efforts would be fruitless.