As the opposition to Philippine President Ferdinand Marcos grows steadily more radical, the Roman Catholic Church here is coming under pressure from different sides.

In addition to divisions on several issues between church and state, some activist priests and nuns appear to be growing more openly sympathetic with the communist New People's Army guerrillas and more critical of what they regard as a church leadership that is too conservative. While this activism is often welcome among the Philippine poor, some Catholics resent it as excessive meddling in politics.

Also at issue is the role of foreign clerics, especially American missionaries from the Maryknoll society, whose activism has been especially controversial.

While the Catholic Church has no official role in affairs of state here, its views are considered important because of its great influence among the nearly 50 million people. About 83 percent of the population -- including Marcos -- is Catholic, making the Philippines the only predominantly Catholic country in Asia.

Under the Marcos administration, the church has generally taken an opposition role on several issues. For example, not only has it opposed the government's family planning policy on religious grounds, but its leaders have spoken out against restrictions on press freedom, human rights abuses, exploitation of Filipino workers by large corporations and construction of a nuclear power plant in Bataan.

In what was seen as a gesture to the church, the government recently gave permission for two Maryknoll priests to return to the Philippines -- after having barred them last summer on charges including sedition, inciting strikes and encouraging Filipinos to join the New People's Army.

The two, the Revs. Ralph Kroes and Edward Shellito, had been assigned to the Tagum diocese on the troubled southern island of Mindanao, where communist guerrilla activity has been on the rise. Church leaders vigorously denied the government's charges against the Americans and pressed for their readmittance.

Church officials said the U.S. priests might have been too aggressive in pressing charges of military abuses and unfair labor practices in the area, but that their actions were not seditious.

However, a senior constabulary officer in the region said, "A thin line separates the ones who are engaged in ecclesiastical work and those who are engaged in subversion. There's no problem if they engage in social work, but I prefer this to be done by our nationals." He added that the Maryknoll priests "also need a little rotation" from time to time.

Another source of controversy has been the case of the Rev. Godofredo Alingal, a Filipino Jesuit killed by unidentified gunmen last year in Mindanao's Bukidnon Province. A longtime critic of military abuses, Alingal had been scheduled to testify in court against an officer accused of rape.

Although several persons witnessed the slaying, no arrests have been made in the case.

One of the latest church-state disputes stems from plans by the U.S. Agency for International Development (AID) to phase out $10 million a year in food aid to the Philippines.

Marcos has said he was not worried about the reductions because the aid was not needed and that the Philippines actually should be extending food assistance to other countries.

Cardinal Jaime Sin, archbishop of Manila and the Philippines' leading Roman Catholic prelate, said Marcos' "grandiose announcement" could endanger food aid totaling $100 million a year to a country in which an estimated half of the population lives below the poverty line.

In an interview, Sin said poverty was the country's biggest problem. He said the United States should continue its food, educational and agricultural aid programs instead of diverting assistance to military projects.

Sin said the church was following a policy of "critical collaboration" with the government. He cited human rights abuses and increased "militarization" as focal points of church criticism, attributing "some little improvement" on human rights this year partly to the church's activities.

Sin stressed that the church was "not interested in the system of government."

"The church has to guide our people, and in guiding them it has to creep into politics occasionally," he said. "But the church will never engage in partisan politics."

Sin conceded, however, that some clerics had joined the New People's Army.

"I can't understand why a priest becomes a Marxist," he said. "If he becomes a Marxist, he is no longer playing the role of a priest. It happens when a priest continues to listen to the despair of the people. It's like brainwashing. It happens and is happening."

Some other church leaders feel that their institution has not done all it could in defending the rights of poor Filipinos, thus allowing the leftists to move into the forefront of the struggle.

"The communists have gotten all the good press by saying they've done all this for the poor," said the Rev. James Ferry, Maryknoll's tough-talking regional superior from New Rochelle, N.Y.

"There has been for a long time here an attempt to silence the Catholic Church," he said. "The church is the only opposition to a lot of the injustice that exists today." For example, he said, the church was "trying to talk to multinationals to ask what they're doing with their money to benefit the people."

Ferry added, "We will be misunderstood as friends of the communists. It's a risk. But I know of no Maryknoll priest who supports what the communists want either politically or militarily."

Some seem to come pretty close, however. They speak sympathetically of the goals of what they call "the movement." Some Filipino clerics clearly have thrown in their lot with the revolutionaries without actually joining the New People's Army. They argue that this is necessary to maintain Catholic influence with the guerrillas, many of whom are not communists, in case a revolution ever comes about.

According to a Maryknoll priest on Mindanao, "There is an attempt now to organize a group of church people involved in the movement" by reviving an organization called Christians for National Liberation. The government has said the group was allied with the Communist Party.

"There are Christians in the movement who are Marxist in some sense or other," the Maryknoll priest said, and they accept the Marxist analysis of the Philippines' situation and follow Maoist revolutionary theory.

The priest conceded, however, that he sometimes suspected the communists of manipulating the church in a self-serving way and believed their attitude might be different if they ever came to power.

"It's an open question how vicious they would be," said the priest, who has contacts in the New People's Army. "We could see something like Vietnamese reeducation camps" for government and military officials. In addition, he said, "I think there would definitely be people targeted for execution."

In Manila, an activist nun linked grass-roots clerical support for the New People's Army with a desire to follow the example of Jesus by working for the poor.

She said the guerrillas and activist clerics "perhaps share an analysis of the Philippines' situation. We see the poverty of the people, the atrocities and the militarization going on."

She added that "if a revolution is the product of the people's decision, I think it will improve the situation."