Patricia Derian, the new State Department human rights coordinator, began "unofficial" talks today with human-rights groups, U.S. embassy staff and Argentine officials on current conditions here and the reaction to President Carter's rights policies.

Derian, whose appointment March 5 has not yet been confirmed by the Senate, arrived Monday, with U.S.-Argentine relations the most strained since the military junta ousted Former President Isabel Peron a year ago.

The one-stop trip, scheduled to last until Friday, indicates that Carter plans to use the rights job, and Derian, as an active part of his human-rights policy. Under the Ford administration, the other half of its mandate, and was less active in human rights.

The junta has made no official comment on Derian's visit, and local press mention has been restricted to an announcement of the visit, without including dates.

According to one high-level government official, however, the junta has no objection to Derian's visit, and in fact "welcomes the opportunity for her to see what Argentina is really like." The official said Derian probably will make contact with the Foreign Ministry, but will not see anyone of Cabinet level because "she hasn't asked to."

The visit follows extensive U.S. and international criticism of the junta's alleged imprisonment and torture of suspected subversives. Early this month, Carter proposed halving U.S. military aid to Argentina, along with cut to Ethiopia and Uruguay, because of human-rights concerns. The junta angrily rejected the remaining $15 million aid proposal and labeled Carter's action "interventionist" and an insult to the Argentine people.

A recent Amnesty International report was also rejected by the junta as "hearsay evidence [that] lacked veracity and objectivity." The report alleged "gross violations" of human rights and charged that the junta has detained "5,000 to 6,000 political prisoners, the majority of which have neither been charged nor tried."

The fact that Derian's trip comes even before confirmation is evidence not only of Carter's continued human-rights offensive, but also of a somewhat delicate measure-taking among the administration, the State Department and countries singled out as rights violators.

According to several sources, the idea of the trip - never formally announced - originated before Derian's nomination was made public, with a personal invitation from U.S. Ambassador Robert C. Hill.

The intention, one State Department source in Washington said, was to "burden her with the truth" about Argentina, seen through the eyes of Americans who live here and the Argentines themselves.

Many embassy personnel feel unjustly maligned by the U.S. press and congressional criticism, particularly resenting that the embassy's report on human rights in Argentina, released by a House committee Jan. 1, was labeled in some quarters as "too soft" on the junta.

They also join many Argentines, both pro- and anti-junta, in feeling that the aid cutoff and the way it was announced, with Argentina sharing the negative spotlight with Ethiopia and Uruguay while South Korea and the Philippines were spared because of their strategic importance, was heavy-handed.

Nixon-appointed Hill, in an interview filmed here last month for columnist William Buckley's "Firing Line" television program, said the United States should concern itself with its own problems "before interfering in the affiars of other nations."

According to extensive press accounts here, Hill said he does not like "the role of policeman" and appealed for "respect and understanding, not sanctions." He also criticized U.S. journalists abroad for "giving greater relevance to the bad" news.

When Derian was nominated as human-rights coordinator, the State Department source said, a lot of people were "scared to death" that she would be a tool for rights activists. A former deputy in the Carter-Mondale campaign, Derian was an outspoken civil-rights activist in the South.

Her initial meeting with the embassy staff yesterday was characterized by one member president as "a meeting between adversaries" where she "laid it on the line that she, and Carter, are very serious about what they are doing."

One member of the U.S. military team here, the staffer said, noted that the aid cutoff made it difficult for them to operate and asked what direction military relations with Argentina were going to take.

Derian reportedly replied: "Well, we're not going to be selling them themscrews any more, if that's what you mean."

For its part, the junta says it has no intention of complying with the strongest U.S. request - that of releasing the names of all political prisoners and those killed since the military took over.