When the Catholic Church's Vicariate of Solidarity was founded here three years ago, Chile was in one of the most difficult periods in its recent troubled history.

Tens of thousands of children were suffering from malnutrition. Unemployment has reached almost 10 percent in Santiago and Chile's secret police had unlimited powers to detain - and many believe to torture and kill - those considered to be leftist opponents of the right wing military government.

The situation was so grave that Cardinal Raul Silva Henriquez decided the church here had an unavoidable repsonsibility to help the poor and the persecuted, even if Chile's military rulers interpreted the work as a form of political opposition.

Such a reaction seemed probable; the junta had just demanded dissolution of an ecumenical church group that had played a similar role.

It was against this background that the Vicariate, which has now been nominated by several groups in Europe for the Noble Peace Prize was started. It became probably the most effective effort on behalf of human and social rights ever undertaken by the Catholic Church in Latin America.

"What they have done is remarkable, really remarkable," said a Latin American diplomat, whose own country has had human rights problems on the scale of those in Chile when the Vicariate was created.

"The church in Chile has been very determined and very brave in defending basic human rights. One could not say the same for the church in Uruguay or Argentina," he said.

The government has insinuated "that the Vicariate is a church-backed effort to undermine the government and keep alive leftist causes taht the military has vowed to stamp out. Christian Precht, 38, a priest who has headed the Vicariate since its inception, was called a traitor by a government-owned newspaper a few months ago. Several members of the staff were arrested recently.

Through all of this,the Vicariate has continued to provide free legal assistance to persons arrested for political reasons as well as free medical care for thousands of the poor. In addition, it runs some 300 lunchrooms around Santiago, where more than 25,000 children receive milk and hot lunches. It seeks to inform Chilans of their rights under such documents as the U.N. Declaration on Universal Human Rights, which past Chilean governments have signed and the current one has not repudiated.

"We do not create conflicts. The facts are conflictive. And when you face the facts then you enter into conflicts," said Precht, referring to the Vicariate's skirmishes with the government. "We are not the ones who have created malnutrition or detention for political reasons or unemployment. We are the ones trying to alleviate these problems that do exist in Chile today."

Perhaps the msot controversial Vicariate cause has been the hlep and publicity it has given to the families of more than 600 persons who have disappeared, presumably taken by Chile's secret police between 1974 and 1977.

Virtually all were members of various leftist groups or were union leaders. The Vicariate and other human rights groups outside Chile have documented that many of those who disappeared were last seen alive in secret police torture centers or detention camps that existed here after the 1973 coup.

It is a problem that government clearly would like somehow to fade away because, in the words of the wife of one of the missing persons, Apolonia Ramirez Caballero, "the government would have to admit it committed genocide if it admitted that it killed our husbands, our fathers, our sons."

It is a problem that the relatives of those who disappeared refuse to let the government forget - and it is a cause the Vicariate and Precht support by providing information about those being looked for and meeting space for their relatives to plan the demonstrations and hunger strikes that they have used to dramatic their cause.

The government has suggested that the Vicariate by defending the relatives and supporting their efforts to find out what happened, is engaged in political activity designed to help enemies of the regime.

But the government has been unwilling to risk a direct confrontation with Cardinal Silva, who has strongly supported - and protected - the Vicariate. Precht insists its only purpose is a "mission of mercy" grounded in the church's doctrines of services and charity.

Within the Vicariate, there are individuals of strong political beliefs, ranging from centrist Christian Democrats to left-wing Socialists and probably Communists. They have come together to oppose the military government and, according to some staff members have also come to understand and tolerate one another in ways that would have been impossible before the 1973 coup.