More than 60 clergymen, including the executive director of the Council of Churches of Greater Washington, joined boxing champion Larry Holmes and 250 other demonstrators outside the South African Embassy yesterday in the continuing protest against that government's policy of racial segregation.

Three prominent local ministers -- two Baptists and a Presbyterian -- were arrested, bringing to 55 the number of persons charged since the "Free South Africa" movement was started here Nov. 21.

In New York, 15 persons who blocked the entrance to the South African consulate on Park Avenue were arrested yesterday and charged with disorderly conduct, according to police. They said 88 persons have been arrested since demonstrations there began 10 days ago.

Joining protesters in Washington on what organizers dubbed "Interfaith Day" was International Boxing Federation heavyweight champion Holmes, a charter member of Artists and Athletes Against Apartheid. Flanked by three bodyguards, Holmes promised to continue the battle against white minority rule in South Africa and vowed, "This is one fight I'm going to win."

The Rev. Ernest Gibson, executive director of the Council of Churches of Greater Washington and one of the three arrested here yesterday, said, "The Council of Churches looks with horror and repulsion upon the South African government, which kills and maims" its citizens.

Gibson declared Sunday, Dec. 23, as "Free South Africa Sunday," and called upon "each church, synagogue and mosque" in the city to take part in a candlelight vigil that will form every day outside the embassy during Christmas week.

He then walked to the embassy, where he linked arms with the Rev. M.A. Covington, pastor of Washington's First Baptist Church, and the Rev. Edward White, pastor of the National Presbyterian Church of Washington, and sang a chorus of "We Shall Overcome." The three men then were arrested.

The American Jewish Committee will organize the antiapartheid demonstration at the embassy on Christmas Day "so that our Christian friends can take the day off," Hyman Bookbinder, the group's Washington representative, said yesterday by phone.

"We are pleased to be able to take up the vigil," said Bookbinder, who said committee members have participated in various antiapartheid protests but had never before staged a "Jewish-organized" event. "We are showing our friendship and cooperation with the Christian community in this most important activity," he said.