Polish strikers, who have brought virtually all economic activity along the northern Baltic Coast to a halt today ignored an appeal by Poland's powerful Roman Catholic Church for a return to work.

Late tonight, suggestions of a compromise emerged from the Lenin Shipyard, where a special commission has been meeting in an attempt to reconcile the opposing views of the government and strikers on the issue of free trade unions. A spokesman for the strike committee said that a basis for agreement had been reached, but he gave no details.

The problem faced by the commission which is composed of experts representing both sides, is to find a formula that keeps Poland's one-party communist system intact, yet allows workers to feel that their interests are represented by an independent organization.

Meanwhile, Deputy Premier Mieczyslaw Jagielski, who has been leading the government negotiating team but returned to Warsaw for consultations yesterday, appeared on Gdansk television to say that agreement in principle had been reached on most of the striker's demands -- with the exception of free trade unions. He said talks would begin again Thursday on the remaining unsolved problems.

[The Soviet Union leveled its first direct criticism of striking Polish workers Wednesday by charging that "antisocialist forces" are trying to subvert Poland's socialist system. Details on Page A30.]

For most of the day, it appeared as if the government was waiting to see the impact of a rare televised address by Cardinal Stefan Wyszynski, the primate of Poland, who warned the strikers not to push the government too far with their demands for free trade unions.

As anxiety mounted about the outcome of the crisis. Poles exhibited a thirst for information about the negotiations. Many tuned into foreign radio stations, and even usually unread government newspapers were completely sold out by 9 a.m.

The government seems to have mounted a deliberate effort to scare the public with the idea that, unless a settlement is reached soon, Poland stands on the brink of disaster -- because of the deteriorating economic position and the threat of Soviet intervention. Two weeks after the strike spread to the Baltic Coast, the word "catastrophe" is being used increasingly by official commentators.

In his sermon yesterday, delivered at Poland's holiest shrine, the Monastery of Jasna Gora, Wyszynski came to the aid of the communist authorities by calling for calm and warning of the dangers of lengthy work stoppages. His words were couched in carefully chosen language, and he defended the right to strike, but at the same time he described the exercise of this right "as a very costly argument."

The importance attached by the leadership to Wyszynski's speech was illustrated by its unprecedented move to repeat the sermon several times on state radio and television. It was also printed in today's official press. As a Polish journalist remarked, "If Wyszynski can't get them back to work, then there's certainly no politician who can."

Strike leaders initially reacted to the cardinal's appeal with disappointment. But they still seemed unwilling to compromise on their key demand for free trade unions independent of the Communist Party.

Indeed, the strike along the Baltic appears to be spreading every day. In the southwestern city of Wroclaw, 20 factories are reported to have joined the strike and have demanded to be represented by the committee negotiating about 500 factories in Gdansk.

The estimated 80,000 workers on strike in Wroclaw include those in transportation and construction enterprises as well as light industry.

Dissident sources here reported scattered incidents of labor unrest in the western city of Poznan and at Krakow in the south.

In Gdansk, strike leader Lech Walesa reacted to Wyszynski's address by saying that it reflected the danger of a broader social conflict spreading throughout the country. But, responding to accusations that the strikers' action could lead to chaos, he added, "We don't want Poland to be drowned because of us. We want it rich, strong, and happy."

Another member of the strike committee took a more critical attitude. "We did not expect him to go so far in helping the government. We are disappointed, but we understand the delicacy of the church's position."

The strikers do not appear to have been persuaded either by a gravely worded editorial, which appeared this morning in the official Communist Party newspaper Trybuna Ludu. Warning of the "possible danger of anarchy," it reminded its readers that Poland was in the direct security zone of a world superpower, the Soviet Union.

On national television this evening one of Poland's leading journalists, Mieczyslaw Rakowski, also warned of a possible catastrophe if the strikes continued much longer.

Rakowski, who was appointed a secretary of the Central Committee in the latest personnel shakeup, said, "I don't want to frighten people. I am freightened myself . . . Our fatherland is reaching a critical point, the Communist Party has admitted its errors, and we now have to reach a social contract with the working class.

"After the experience of these days, the party, the working class, and society will be different . . . None of us wants to experience a national tragedy."