Poland's deputy prime minster said today that the Communist authorities are ready for a new trial of strength with the independent Solidarity trade union federation on the issue of responsibility for police violence last March in the northern town of Bydegoszcz.

Miecyslaw Rakowski, the deputy prime minister in charge of negotiations with the union, said in an interview with The Washington Post that some radical Solidarity members wished to destroy the government and create further instability in Poland. Thursday night the union leadership decided by 22 votes to 13 to stage a two-hour warning strike in Bydgoszcz next week to press demands for the punishment of former local government officials linked to the violence.

If the strike goes ahead as planned next Thursday, the strike will effectively end a two-month labor truce in Poland and reverse a steady improvement in relations between Solidarity and the authorities. The threat of a strike comes at a particularly delicate time in view of preparations for an extraordinary Communist Party congress and heightened Soviet concern about the pace of reform in Poland.

Rakowski combined his criticism of radicals in Solidarity with praise for union leader Lech Walesa, who is in Geneva for a conference of the International Labor Organization. Rakowski's comments suggested a two-pronged government strategy toward Solidarity: to attempt to win the trust of moderate leaders like Walesa by defusing possible conflicts while facing up to the challenge of the radicals.

At the same time, reformers in the government, Rakowski among them, are aware of the possibility of a back-lash by hard-line members of the ruling apparatus who see power slipping through their hands. With just five weeks to go to the congress, which could produce dramatic changes in the leadership, the political balancing act in Poland has reached a crucial stage.

He also spoke of the Soviet Union's increasing concern at developments in Poland and what he described as the Soviet's "vital interest" in the preservation of Communist Party authority.

The first element in the government strategy, as outlined by Rakowski, was reflected in the release last week of four remeaning right-wing dissidents pending the start of a trial June 15. This conciliatory move, however, was balanced by the adoption of a tough line on attempts to revive the Bydgoszcz controversy.

Solidarity claims that the government has not yet fulfilled its side of an agreement reached at the end of March under which a general strike throughout Poland was called off. The agreement stipulated that those responsible for the beatings of Solidarity activists, including the local union leader, Jan Rulewski, would be "judged according to the law."

Radowski said the government had already publicly apologized for "mistakes" made a tBydgoszcz and described the new strike threat as a pretext for "political struggle against the government." He revealed that in talks with Solidarity on Monday, he would treat the issue as a matter of collective responsibility of the entire government.

Noting that Solidarity demanded that "the guilty" be brought to trial, Rakowski said: "They want to know who was guilty for this incident. Well, I am guilty, the government is guilty. The government has to take responsibilty for it. Do they want us to be put on trial? Well, we are not afraid."

The deputy premier said that, while it was possible to reach agreement with Walesa, there was no basis for understanding with radical Solidarity leaders like Rulewski, who chaired the meeting that decided to go ahead with next week's warning strike.

"The problem is that the radicals within Solidarity are quite numerous," he added. "They were born under conditions of struggle. They can't -- perhaps don't want to -- proceed from fighting to dialogue. Their goal is to destroy the government. They cannot exist without fighting.

"The revival of the Bydgoszcz affair thus has nothing to do with justice. It's just another attempt to provoke a political struggle with the govenment."

The government argues that since the Bydgoszcz incident, much has been done to defuse tension here, including the legalization of an independent union for private farmers and the gradual release of political prisioners. This in turn has provoked expressions of alarm from the Kremlin.

In addition to being the government's chief negotiator with Solidarity, Rakowski is a long-time editor of the influential weekly Polytika. His appointment as deputy prime minister in February was regarded as a conciliatory move toward the union, but he says he is beginning to doubt whether the policy of compromise can really succeed.

"The other side takes it as a sign of weakness and presents us with ever new demands," he said. "Solidarity has begun to conduct itself not as a trade union, but as a social movement. . . . The political ambitions of some of its leaders can only deepen tension in Poland."

He insisted, however, that the government remained committed to its policy of solving disputes by dialogue.

"This is a parallel process," he said. "We have negotiations -- but within the framework of talks, there is room for more than just smiles. We also have the duty to state openly what is on our mind."

Rakowski said it was time that Polish society switched attention away from political struggle to what he described as the more important problem of the more important problem of the economy. He said Western bankers were displaying growing impatience with the continuing industrial unrest and Poland's inability to resolve its economic problems.

"I wish that Solidarity would finally understand that it is in their own interests to cooperate with the government," he added. "If they drag us to the bottom, they will go to the bottom as well. For there is no way that Communists are going to give up power here and allow Solidarity to start ruling."

Questioned about the Soviet attitude toward Poland, Rakowski said the Kremlin was following developments here very closely but was far from taking a decision to invade.

"They are vitally interested in having us strengthen our position so that we can manage the crisis," he said. "They do not meddle in the way we resolve our problems -- as long as we can find ways of avoiding chaos and retaining authority."