President Carter ended the Latin American leg of his four-nation overseas trip, by meeting yesterday morning with six prominent critics of Brazilian government policies to discuss issues ranging from human rights to economic policies.

The encounter took place after two days of official talks in which Carter discussed many of the same issues with Brazilian government leaders. But in contrast to the polite if distant reception the president received in Brasilia, yesterday's meeting took place in an atmosphere that participants later described as "relaxed and informal" and "freewheeling."

Brazilian participants said that the 40-minute meeting, though shorter than they had hoped for, reaffirmed in their minds Carter's commitment to human rights. "We learned that he has the same doubts we have," said human rights lawyer Raymundo Faoro, president of the Brazilian Bar Association.

Leading the Brazilian delegation was Paulo Evaristo Cardinal Arns of Sao Paulo, the nation's leading human rights advocate. Afterwards, Cardinal Arns left the meeting in the presidential limousine, seated next to Carter, and had a separate conversation with the president during the long ride from Carter's quarters high in the mountains overlooking the city to Galeao air base.

The meeting, which took place on the 14th anniversary of the military coup that ended civilian rule and installed an authoritarian regime here, drew criticism from some government quarters. One government party leader in the Brazilian Congress called Carter's meeting with the group an "inelegant" and "unnecessary" gesture.

Participants said, however, that they did not expect any changes either positive or negative, to result from the meeting, whose main purpose was described as psychological. "It's always encouraging to know we're not alone," said Faoro.

Participants in the meeting said that much of the discussion centered on the human rights situation here, with a special emphasis given to the sweeping Institutional Act Number Five, which grants the Brazilian president dictatorial powers.

The Brazilian participants said, however, that there was unanimous agreement between them and Carter that the human rights situation here is improving. Publisher Julio de Mesquita Neto said that Carter "noted that there had been advances in liberty of the press and freedom of expressionsince his last visit here" six years ago.

The Brazilians also said that Carter, accompanied by Secretary of State Cyrus Vance and other American officials, seemed to be well-informed about Brazil's human rights and social Problems. "I don't think we were telling him anything he didn't already know," said Faoro. "We were just refreshing his memory."

Faoro said that the president at one point asked him about the denial of habeas corpus to political prisoners, one of the most important and unpopular provisions of the institutional act. He also reported that Carter showed an interest in the problems of poor homesteaders in the Amazon region.

"But for the most part, the Brazilian said, the president let them do the talking. Carter "listened attentively and said little," reported businessman Jose Mindlin, who, along with National Development Bank head Marcos Vianna, who is said to be an advocate within the Brazilian government of an increased emphasis on social programs and income redistribution, raised economic and commercial questions with the president.

Except for Vianna, all the members of the delegation were private citizens, and most are identified with the opposition to Brazil's military regime. The varied assortment of legal, church, business, and journalistic spokesman was intended, said Faoro, to give Carter "a sense of what some of the important segments of Brazilian society are thinking."

According to participants in the meeting, the president made no specific suggestions or promises in the human rights or economic areas and did not touch on Brazilian internal politics.