Supreme Court Associate Justice Sandra D. O'Connor, breaking an unwritten rule against discussing issues pending before the court, yesterday urged a congressional subcommittee to consider changes in federal civil rights law.

In suggesting new limits on the filing of discrimination suits, O'Connor may have telegraphed her vote, if not the court's judgment, on one of the most important cases on the Supreme Court's docket.

O'Connor and Justice Lewis F. Powell Jr. were testifying on the Supreme Court's budget before a House Appropriations subcommittee. During the testimony they cited the court's expanding caseload as justification for a requested 12 percent increase in its budget.

Asked how Congress might help control the caseload, O'Connor responded that it should consider legislation that would require people suing for damages under the civil rights law to take their complaints first to administrative agencies. This requirement would cut down the number of suits reaching the federal courts, she said.

Civil rights lawyers argue that the federal law at issue, the Civil Rights Act of 1871 (Section 1983), was designed expressly to circumvent state administrative procedures and provide a prompt remedy for constitutional violations.

That O'Connor says she believes administrative remedies should be exhausted before federal courts take up a case is no surprise. She had written on the subject before being appointed to the Supreme Court.

The fact that she talked about it yesterday, however, was unusual. Last week the court heard oral arguments in a civil rights case from Florida raising the question of whether exhaustion of state remedies before the filing of federal damage suits is required either by court precedent or past congressional action.

O'Connor's comment suggests that the court has decided that no congressional action requires the exhaustion of state remedies.

The case under consideration, Patsy vs. Board of Regents of Florida, stems from a sex and race discrimination suit filed by a white woman job applicant.

The 5th U.S. Circuit Court of Appeals ruled that she should have taken her complaint through available administrative agencies before seeking damages in the federal courts.

Reaction to O'Connor's comments yesterday from Supreme Court observers, all of whom requested anonymity, ranged from "shock" at her openness to the view that she had skirted the Patsy case sufficiently to escape charges of breaching the tradition of silence.

O'Connor would not comment when asked whether she believed she had been indiscreet. "I rest on what I said," she said.

Chief Justice Warren E. Burger was criticized sharply last year for a "law-and-order" speech that encompassed issues facing the court.

The budget increase requested by the court is one of the largest sought by any federal agency, although the total budget request for the court, $13.9 million, is minor by most federal agency standards.

Powell noted that in the past two years the court had returned money to the Treasury. But the rapidly expanding caseload, inflation and inadequate budget estimates in prior years required the increase this time, he said.

Powell also had some proposals for reducing the caseload, including congressional action reducing the mandatory docket of the court.