Several thousand television and radio preachers who flocked to a convention here this week to hear such conservative speakers as evangelist Jimmy Swaggart and White House aide Patrick Buchanan largely stayed away from a breakfast yesterday where the Rev. Jesse Jackson was the main speaker.

Black leaders bitterly criticized Natiopnal Religious Broadcasters officials for scheduling the Jackson breakfast simultaneously with a widely promoted pro-Israel prayer breakfast that featured such luminaries as former United Nations ambassador Jeane Kirkpatrick, Rep. Jack Kemp (R-N.Y.) and television evangelists Jerry Falwell, Pat Robertson and Swaggart.

The Rev. Clay Evans of Chicago and other black leaders, who said they were embarrassed and humiliated by a small turnout of only 125 persons to hear Jackson at the "fellowship breakfast," charged that the event had been "sabotaged" by officials of the NRB who are sponsoring the convention at the Sheraton Washington.

NRB officials denied the charge.

"We expected 2,000 people, just like it was yesterday morning" when Swaggart spoke, said Evans, the pastor of the Fellowship Missionary Baptist Church in Chicago and newly elected chairman of the Black Broadcasters Committee, which sponsored the breakfast with the NRB.

About 1,250 people, including many who had no ties with the NRB, attended the Israel breakfast, held in a ballroom near the Jackson gathering. The annual prayer breakfast in support of Israel was initiated five years ago by an independent group headed by Christian right activist Ed McAteer.

"We informed them (NRB officials) months ago" about the Jackson breakfast, said Evans, whose embarrassment was heightened by the fact that Jackson attends his church in Chicago.

"We got slapped in the face," he told reporters after the session.

But Ben Armstrong, the NRB's longtime executive director, denied that his group had tried to undermine the Jackson breakfast and said the black leaders had known in advance that their breakfast would coincide with the pro-Israel gathering.

"I was encouraged by the fact that it (the black leaders' breakfast) was the largest attendance they've ever had," said Armstrong. There are an estimated 80 black members of the NRB and in the past black broadcasters have had little visibility in the predominantly white organization.

"It was the largest (breakfast for blacks) in the history of the NRB," he said. "I would say it rated as a success."

According to Armstrong, the pro-Israel breakfast is held at the same time every year, on the closing morning of the convention.

"It's a case of the blacks not being all that organized. . . . It's just the way it is."

The black broadcasters' breakfast was listed in the broadcasters' program as an official NRB plenary (for all members) session, while the Israel breakfast was not. Jackson told reporters after the blacks' breakfast that it was his understanding he had been invited to address the entire convention, for which more than 4,000 persons were registered.

"I came as a guest," he said. "I expected significant numbers. It became apparent that there was a move to sabotage the efforts of the black broadcasters. . . .

"The issue is not me; the issue is (the white broadcasters)," Jackson said. " . . . For them to express resentment and contempt and to hurt their black religious brothers' feelings is un-Christian."

During the breakfast, the black leaders made only oblique references to the skimpy attendance. The Rev. B. Sam Hart of Philadelphia, retiring chairman of the black broadcasters committee, appealed for funds to cover the deficit from unsold breakfast tickets.

"We felt sure we'd have this ballroom full," he said, blaming the poor turnout on "circumstances of life as it is in the United States."

Armstrong denied that the scheduled appearance of Jackson, a Democratic candidate for president in 1984, created problems among his conservative constituency. But later, at a business meeting, the Rev. Bruce Dunn of Peoria, Ill., protested that he would face criticism from his constituency for participating in a convention that gave Jackson a platform.