The independent trade union federation, Solidarity, today called on millions of Polish workers to stay off their jobs Saturday in support of demands for a five-day week.

On the eve of the planned protest, the government issued a stern warning to union leaders. In a broadcast speech, Politburo member. Stefan Olszowski accused them of seeking to destabilize the country and asserted that the Communist Party would oppose "all counter-revolutionary steps."

Earlier today, the government warned that those who heed the Solidarity call will be docked a day's pay. "An employe has no right to be paid if he stays away" from his job Saturday, a Labor Ministry statement repeatedly broadcast over the national radio said.

Solidarity, which claims a membership of between 8 to 10 million, maintains that the government had reneged on its pledge last summer to give workers every Saturday off without pay reductions, starting this year.

The call for a nationwide demonstration came as Moscow issued another sharp attack on "enemies of socialism" in Poland whom the Soviet government newspaper Izvestia accused of promoting "counterrevolution."

Izvestia said that "in recent days the enemies of socialism activated their undermining activities" in an effort to give "political character" to the new unions.

The Polish armed forces newspaper Zolnierz Wolnosci also attacked dissident leader Jacek Kuron, who is a member of a special Solidarity panel, for allegedly seeking to turn the unions into a "political party" and proposing changes that would subvert Poland's socialist system.

Most Poles work a six-day, 46-hour week of five eight-hour days and a sixth, six-hour day. The government say Poland's beleaguered economy cannot afford the luxury of a 40-hour week and said it planned to phase in reduced working hours.

Today, the union's Warsaw chapter declared "all Saturdays are free beginning Jan. 1, 1981," adding that "any repression against employes will meet decisive action from the side of Solidarity."

Solidarity contends the government promised "free Saturdays" as part of the Gdansk agreements that ended the wave of strikes last summer and were fllowed by the ouster of Communist Party leader Edward Gierek's government. Other provisions of the agreements provided for the establishment of the first independent labor union in the Soviet Bloc and access to communications media for the strong Roman Catholic Church.

Deputy Premier Mieczyslaw Jagielski, who negotiated the Gdansk agreement, said the government wants to phase free Saturdays in over a five-year period. He said the government has proposed two alternatives: two Saturdays off per month or all of them free but with an extra half-hour of work on each working day.

In hopes of avoiding a major showdown, management at some plants throughout the country was reportedly considering declaring a holiday on Saturday. At a Warsaw electronics plant, even the old, state-backed branch union joined in calling on workers to stay home. A source at the plant said the two rival unions decided on a joint call "following negotiations."

The Saturday protest signaled an end to a Christmas labor truce. The action would be the first nationwide protest since early November, when Solidarity declared a "strike alert" in connection with a Supreme Court hearing on its applications for registration.

In a related development, the party journal Nowi Drogi today printed a letter from Gierek addressed to his successor Stanislaw Kania and the Central Committee in which Gierek defended his 10 years in power and said he was responsible for the major decisions made in that time.

"Were they right decisions? The answer to this quesition is difficult and depends on the viewpoint.I want you comrades to be convinced that I always wanted good [for Poland]," Gierek said in his first public statement since his ouster.