Soviet husband-and-wife skating stars Oleg Protopopov and Ludmilla Belousova have asked for political asylum in Switzerland, Swiss officials disclosed yesterday in Bern, marking another startling crossover in a recent run of defections by well-known Soviet artists.

A spokesman for the Swiss government said the skaters' request came last week while they were on tour, but a decision on it would not be made for "several weeks."

As a sign that they are not averse to such pleas, however, the Swiss also chose yesterday to announce that asylum had been given to Soviet Chess grandmaster Viktor Korchnoi, whose earlier petition for asylum in the Netherlands had been rejected by the Dutch.

The announcement of the skaters' defection added one more embarrassment for a Soviet government that is still smarting over the loss of three Bolshoi ballet stars who defected during a U.S. tour within the past month.

Alexander Godunov left the Bolshoi at the end of August, seeking asylum in New York. His wife, Ludmilla Vlasova, was subsequently held for three days at Kennedy Airport before U.S. officials accepted assurances that she wanted to return to the Soviet Union. Then last week, Leonid Kozlov and his wife, Valentina, slipped away from the ballet company in Los Angeles when the tour ended.

But the crossover of the Protopopovs is likely to strike the Soviets particularly hard. The skating couple had been celebrated not only for their athletic prowess but for their exemplary citizenship as well. Both were Communist Party members. And among the many honors bestowed on them by Soviet officials was the prestigious title "Masters of Sport of the Soviet Union."

The 47-year-old Protopopov and 43-year-old Belousova had been the aging stars of the Soviet ice rink. They dominated world figure skating in the 1960s, twice gliding off Olympic rinks with gold medals. Since retiring from competition in the early 1970s, they had been teaching and taking part in various traveling ice revues with a troupe based in Leningrad, their hometown.

Early last week they dropped from public sight in Zug, near Zurich, at the end of a four-week skating tour through West Germany and Switzerland.

Their Swiss host and tour organizer, Kurt Soenning, sounded as surprised as the Soviets when public notice of the defection came."Never did they drop the slightest hint that they were planning to stay in the West," he was quoted by Associated Press as saying. "If they had, I would never have invited them."

At the same time, Soenning recalled that the couple had arrived in the West with a surprisingly large amount of baggage -- 10 pieces in all. "He brought a videorecorder and she even a sewing machine," Soenning said. "I joked about it then. Now I know why they brought all this."

Swiss officials offered no reasons for the crossover. They declined to reveal the skaters' current whereabouts or discuss the Protopopovs' plans.

But Soenning hinted at what may have been one trigger for the defection, saying he understood that Protopopov had frequently quarreled with officials of his Leningrad troupe because he thought the rinks they selected for performances were too small.

Protopopov, a teacher by profession, and Belousova, an engineer, were married in 1957. They rose to world fame at the Olympic Games in Innsbruck, Austria, in 1964, dethroning defending gold medalists Marika Kilius and Hans-Juergen Baumler of West Germany. They won four successive world championships in the years following and another Olympic gold medal at Grenoble, France, in 1968.

The couple last appeared in international competition at the 1969 world championship in Colorado Springs, Colo., where they placed third, losing their title to another Soviet pair, Irina Rodnina and Alexei Ulanov, who went on to win the 1972 Olympic title.

Many young Soviet ice skaters modeled their style after the Protopopovs, who are credited with developing a unique skating style, including a range of movements borrowed from ballet.

Meanwhile, the granting of asylum to Soviet chess star Korchnoi ends a three-year search by the grandmaster for a new country. He defected in the Netherlands in 1976 and has lived for two years in the small eastern Swiss town of Wohlen.