The United States intends to prod the U.N. Human Rights Commission into addressing the [WORD ILLEGIBLE] of rights violations in Third World countries rather than confining itself to repeated condemnations of South Africa, Chile and Israel, the new chief U.S. delegate said yesterday.

The commission whose annual session opens here today, has traditionally singled out these three countries in human rights violators and has generally ignore charges against communist countries and black African dictatorships.

This year, according to Edward Brezvinsky, the chief U.S. delegate, the United States plans to be "much more vocal and upfront about Uganda, Cambodia and Equatorial Guinea."

In addition, Mezvinsky, a former Democratic congressman from Iowa, said, the United States will take a close look at any progress in implementing the confidential procedure set up by the commission for the handling of rights violations.

"We want to test whether procedures under the Human Rights Commission really work," Mezvinsky said in an interview.

Last year, by bringing up the problems of Soviet dissidents, the United States tried to push the 32-member commission, whcih is dominated by Communists and Third World countries, out of its "straightjacket" of confining itself to the "unholy trinity", as the then U.S. delegate Allard K. Lowenstein, a former New York Congressman, put it. The United States lost on procodural manuevers.

Mezvinsky, whose easy-going manner contrasts with Lowenstein's intensity, is admant that the commission must expand its attention to specific nations that violate the human rights spelled out in the 1948 Universial Declaration of Human Rights and more recent international conventions.

Feeling it best to handle delicate problems with regional involvement, the Americans here plan to spend time with African delegates in hopes of establishing a working group including Africans to deal with the human rights situation in Uganda.

The U.S. delegation here will also be pushing to create a new U.N. office - high commissioner for human rights - which would upgrade the level of bureaucratic machinery dealing with human rights issues. There is hope that the General Assembly will establish a commissioner next year.

It is possible that this year there will not be, as there was at last year's session, a dramatic showdown between U.S. and Soviet delegates over dissidents in the Soviet Union. The United States is continuing to focus on the Belgrade conference reviewing the Helsinki accords for a lower keyed exchange over human rights in Eastern Europe.

More subtle differences my surface here, however as they have at the U.N. General Assembly, between the United States and developing countries over priorities in the human rights field.