Irina Orlov, the wife of dissident physicist Yuri Orlov, was stripped nude except for her bra in front of three security men yesterday before she was permitted to leave the courthouse following the third day of her husband's trial on charges of anti-Soviet activity.

She told reporters later that the incident took place after the prosecution asked the court to sentence Orlov to the maximum penalty of seven years imprisonment followed by five years of internal exile. The verdict and sentence were expected to be announced today.

Mrs. Orlov, 33, was able to give Western correspondents her account of yesterday's court proceedings after a dramatic 45-minute drive through Moscow to reach a correspondent's apartment.

Three carloads and KGB secret police chased the correspondents and the Orlov family through the city, cutting off following vehicles and running red lights to play "bumper tag" in thick traffic with their quarry. The KGB took movies of the correspondents' cars and filmed Mrs. Orlov going inside a building with the correspondents.

Scuffling broke out near the courthouse Tuesday when police agents attempted to brief dissident friends and Western reports about that day's proceedings. An even larger crowd milled outside the courthouse yesterday and police had again warned against any sidewalk press.

Once inside the apartment, Mrs. Orlov told how she had been stopped on her way out of the courthouse and taken to a special room to be searched. "They peeled off my clothes, even my stockings and the men didn't turn away," she said. She said she was left only in her bra.

The KGB had confiscated a tape recorder from each of Orlov's two sons in a search following Monday's proceedings. Mrs. Orlov and the 53-year-old physicist's two sons from his first marriage are the only spectators permitted in the courtroom which is packed by officially selected "representatives of the public."

Orlov family members said the handpicked "crowd" yesterday repeatedly interruped Orlov as he sought up to deliver his summation speech. They cried "traitor" and "spy". The judge also interrupted the summation "every three minutes" and cut Orlov off after 30 minutes. Orlov was again refused permission to call any defense witnesses.

Orlov, who founded a group to monitor Soviet compliance with the provisions of the 1975 Helsinki agreement on European security and cooperation, is charged with spreading anti-Soviet propaganda and slandering the state.

The monitoring group had issued a number of reports on violations of human rights which the Soviets have pledged to observe under the Helsinki accord.