The Supreme Court yesterday delayed the effect of a Dec. 23 lower court ruling on ratification of the Equal Rights Amendment, temporarily removing what ERA supporters described as an "excuse" for state legislators to oppose the ERA.

But the court put off consideration of the major issues in the case, probably until after the June 30 ratification deadline.

The court's complicated and unusual action left both sides claiming victory although none of the parties had formally asked the court to do what it did yesterday.

In fact, the battle at the court has become largely a public relations struggle and any victories were symbolic.

U.S. District Court Judge Marion Callister, in Boise, Idaho, ruled on Dec. 23 that Congress had acted unconstitutionally when it extended the ratification deadline from 1979 to 1982. He also ruled that states could rescind legislative votes ratifying the amendment. Five states claim to have done that.

The lower court's action had no real legal effect because it didn't prevent legislatures from considering the amendment. But ERA supporters contended it had a psychological effect on deliberations in state legislatures. They hope that a negative "cloud" is removed by the stay issued yesterday by the full court.

Anti-ERA forces, who had hoped to keep the cloud there, were claiming victory yesterday because the justices refused to issue a speedy ruling on the major issues involved in the case.

Only 35 of the required 38 states have approved the amendment. Recent setbacks for ERA supporters in three more states suggest that the frantic struggle may not succeed by June 30, regardless of yesterday's Supreme Court action.

When the battleground had shifted to the Supreme Court after Callister's ruling in December, the parties to the case fought most vigorously over the question of when the justices should act.

Pro-ERA forces wanted the court to dispose of the ruling as quickly as possible, either summarily or by an expedited review before legislatures adjourn across the country. Opponents hoped to drag out the court's consideration until it became hypothetical, as far as the ERA is concerned, on June 30.

The Reagan administration, which is a party to the case on the side of the National Organization for Women, suggested that the court immediately nullify the ruling without rendering an opinion on the merits.

No one asked the Supreme Court to stay Callister's ruling, as the justices did yesterday. No one thought there was anything, legally speaking, to stay. Callister issued no orders when he ruled last month.

That made yesterday's action unusual, even "bizarre," in the words of one lawyer involved in the case, for it appeared that the justices, too, were acknowledging the symbolic impact of Callister's action by issuing their own largely symbolic stay.

Without comment, the court delayed the ruling, agreed to review it and denied the NOW request for expedited consideration with hearings in early February.

The court's hearing schedule is already filled up for this term. Without additional instructions from the justices, arguments probably cannot be held until next fall.

Eleanor Smeal, president of NOW, said in a telephone interview from Oklahoma, "We think it is an important victory, an extraordinary ruling which suspends Callister's ruling. Basically, they've cleaned the slate for us. What the court did was give us, in practical results, what we asked for."

Smeal said the Callister ruling has been used against the ERA by opponents in Oklahoma where she and other NOW members are lobbying for ratification. She said the decision by the Supreme Court will give state legislators "one less excuse" for voting against the ERA.

Laurence Tribe, Harvard professor and NOW lawyer, pointed out that under Supreme Court tradition, stays are not issued unless the court believes there is a likelihood that the lower court was wrong in its ruling. It is "an indication that the court has difficulty with the Callister ruling," he said.

But anti-ERA leader Phyllis Schlafly also claimed success. "I think this is a tremendous victory for constitutional integrity. I'm very pleased at the ruling, pleased that the court rejected the request for expedited review by the justices by NOW and 46 other organizations and the speaker of the House and the American Bar Association," she said in an interview from her home in Illinois.

She said she does not believe the decision will have any effect on the ERA. "I don't think anything that happens in the court case can possibly save ERA. ERA is dead," she said.