Pope John Paul II met today with the hierarchy of the Roman Catholic Church of Brazil, the largest in the world, to warn them about the "grave consequences" of straying too far from Vatican dogma in pursuing an active political and social role in their society.

Having called together the 21 leading prelates of Brazil for a unique three-day disciplinary "dialogue" with Vatican officials about their church's often controversial activity in Brazil, the pope cautioned today that he was not opposed to the so-called "theology of liberation" that has been a predominant model for the Brazilian church, as long as it was "purified of elements that could adulterate it."

The pope's comments came at the opening session of the extraordinary meeting with Brazilian prelates that Vatican officials chose to call an "informal dialogue" today. But other church officials, who asked not to be named, said it was nothing less than a call to order by the pope to one of his most important, and autonomous, local churches.

Independent church sources here said the gathering represented the latest in a series of efforts by the pope and his guardian of Catholic orthodoxy, Cardinal Joseph Ratzinger, to reimpose traditional Vatican dogma on local churches. Since the Second Vatican Council of 1962, a number of those churches has shown growing involvement with pressing social, economic and political issues.

The so-called theology of liberation, pioneered by Latin American theologians and prelates 20 years ago, has in extreme cases even borrowed from atheistic Marxism to analyze the ills of the impoverished and repressed in Latin American cities. It lies at the heart of the Vatican's dispute with various leading local churches such as the 135 million-strong Brazilian church. According to Brazilian church sources, today's meetings at the Vatican are aimed at smoothing over, if not reversing, Brazil's divergence.

In 1983, the Vatican made its first onslaught against the theology of liberation, which had been increasingly embraced by progressive clerics in Latin America. The Congregation for the Doctrine of the Faith issued an "instruction" to the universal church attacking the neo-Marxism of some liberation theology doctrine. Today, in his opening speech to the leading prelates of the Brazilian episcopal conference of 365 bishops, the pope confirmed that "soon" the congregation would issue another "instruction" detailing the limits of Vatican tolerance of liberation theology.

That theology, and its central doctrinal tenet of a church's "option in favor of the poor," was specifically defended today by the pope as long as it does not deviate from the central church's doctrine .

"I want to confirm that a theological reflection on liberation can and must exist, founded on solid doctrinal elements pertaining to the most authentic magisterium of the church," the pope said in the opening speech of the closed-door meeting. "The church considers it her duty to continue, put into practice and deepen this reflection more and more.

"Purified of elements that could adulterate it, with grave consequences for the faith, this theology of liberation is not only orthodox but necessary," the pope said. It was seen as an effort to reassure those among the Brazilian hierarchy who have embraced the theology as the only means of making the church relevant to the population, the vast majority of whom are impoverished peasants and starving slum-dwellers.

But Brazilian church officials here remained skeptical of the Vatican's intent to back a genuine theology of liberation, noting that Ratzinger's congregation last year silenced the Rev. Leonardo Boff of Brazil, a leading Franciscan liberation theologian, by banning his writings.