Cardinal Stefan Wyszynski, Poland's chief Roman Catholic cleric, said a private mass today for strike leader Lech Walesa, then embraced and kissed the labor champion in an important show of unity between the heads of Poland's oldest and newest mass movements.

The granting of a special audience to Walesa amounted to an official blessing by Poland's powerful Catholic Church for the independent labor unions won by striking workers. It came on a day when Poland's official radio warned workers still on strike in several cities that further demands could jeopardize agreements already reached between the government and strikers.

The radio cited the country's "difficult" economic situation and called the continuing strikes in northern and southern Poland "alarming."

"Any further demands, however justified, even urgent and necessary, may place a question mark over the implementation of the undertakings already given," the official radio said.

Today's meeting between Walesa and Wyszynski marked a reconciliation of sorts between the Polish strikers and church authorities, who had urged workers to go back to their jobs at an earlier stage, before final agreement was reached in the dramatic confrontation with the country's communist leadership.

With 75 to 80 percent of Poland's 35 million people practicing Catholicism -- despite the state's official atheistic ideology -- the church wields enormous power here and frequently has been at odds with the party.

But senior church officials, while voicing understanding for workers' aims, had feared a prolonged protest would lead to a violent end.

The workers, many of them devoutly Catholic, ignored the pleas to stop striking and kept to their militant faith. They created a shrine at the fence enclosing the Lenin Shipyard in Gdansk and arranged for confessions to be given in the yard that formed their headquarters.

In signing the historic 21-point labor settlement with the government last week, Walesa used a long pen that bore the picture of Polish-born Pope John Paul II.

While spokesman for Walesa and the cardinal each claimed the other had initiated today's meeting, both parties had much to gain by it.

For the workers, it was a further sign of legitimacy for their fledging free union movement. For the church, it was the chance to make amends for what may have been a misjudgement of the strikers' resolve and the odds that they could eventually achieve their demands.

By meeting a day after the Central Committee named Stanislaw Kania to replace Edward Gierek as party chief, Walesa and the cardinal appeared to feed the pressure for reforms. Poland's persisting labor trouble seems to stem now largely from local or regional gripes.

"It's like the measles," observed one Western diplomat of the continued strike actions. "Everyone feels he has to go through it."

But there was a sign today that worker troubles could escalate again. A state farm near the southeast town of Lubaczow was reportedly on strike demanding independent unions, a concession won by striking shipyard workers following Walesa.

While much of Poland's farmland is still in private hands -- to the distress of efficiency experts and government planners -- 40,000 people live on state-run farms. A mass decision by them to leave the fields could easily throw Poland into another crisis.

In another twist, workers in Bialystok -- a major industrial center in northern Poland -- were said to be demanding the ouster of some unpopular local politicians. According to dissident sources, the same was being asked in the sulphur mining town of Tarnobrzeg, where 11,000 workers are on strike.

This could pose a more threatening attack on Communist Party rule than did the call for independent trade unions. Such demands could reflect the new-found political weight of Polish workers, buoyed by the concessions they have already won.

In Warsaw this morning, Walesa, the 37-year-old devout Catholic electrician, was ushered into the Polish cardinal's small private chapel for an 8 a.m. mass. He was accompanied by a 16-member delegation of workers and Baltic area church officials who had driven with him from Gdansk last night.

During the service, the cardinal reportedly delivered a 10-minute homily stressing the "need for human love and brotherhood" and commending Walesa for showing these qualities during a difficult time.

The cleric, generally regarded as politically astute, also expressed relief that the strikes had ended peacefully, according to a Walesa associate who was there.

Afterward, as Walesa stood with some associates outside the chapel, Wyszynski emerged and moved to embraced and kiss the mustachioed labor leader. w

Walesa, along with several fellow workers, then had breakfast with the cardinal at his residence near Warsaw's medieval Old Town. Also present were Polish episcopate secretary Bronislaw Dabrowski, Gdansk Deputy Bishop Kazimieri Kluz, and local Gdansk parish priest Henryk Jankowski.

Walesa was said by an associate to seek the cardinal's counsel on how to organize the new unions.

Emerging from the residence, Walesa, wearing his perenially wrinkled brown suit, dodged reporters and ducked quickly into a waiting car. The delegation then sped back to Gdansk to attend a special afternoon mass in celebration of the labor agreement signed there.

News services reported these related developments:

Soviet President Leonid Brezhnev sent former party chief Gierek "wishes for earliest recovery" from what has now been specified as a heart attack suffered Friday, the Soviet news agency Tass said.

The official daily Zeri i Popullit of the hard-line Albanian Communist Party condemned the Polish accord on independent unions as a "shameful defeat" and "platform for the new reactionary forces in Poland."

A British Foreign Office spokesman said Foreign Secretary Lord Carrington plans to visit Poland and Hungary in late October. The visit should not be interpreted as an immediate reaction to the recent changes in the Polish leadership, the spokesman said.