PRETORIA, SOUTH AFRICA, JAN. 7 -- Black students failed a recent round of high school graduation examinations at the highest rate in South Africa's history, the government reported today, underscoring the crisis in black education here and the gaping disparity in quality between white and black schools in this racially segregated society.

Only 36 percent of the 233,000 black students who took the tests in the last two months of 1990 passed, according to the Department of Education and Training, compared to 42 percent the previous year -- a drop of 14 percent. The pass rate for whites was 97 percent, for Asians 95 percent and for those of mixed race 79 percent.

Equal education is a principal concern for blacks and whites as this white-ruled country seeks to shift from the apartheid system of racial separation to multiracial democracy.

Black groups, who branded today's results "disastrous," see quality education as the key to the economic and political advancement of South Africa's 21 million blacks, while many of the nation's 5 million whites fear the end of school segregation would lead to sharply lowered standards for their own children.

Officials in the Department of Education and Training, which deals only with black education, blamed the results on the failure of black parents and political leaders to persuade a "lost generation" of militant youths to return to school after several years of political activism. They also said strikes by students and teachers wasted nearly 20 percent of the school year.

Given the wide range of problems, the results could have been much worse, Education Minister Christoffel J. van der Merwe told reporters. "This is a very poor result, but on the other hand, if one looks at the situation that obtained during 1990, then I think there is a lot to be thankful for," he said.

But black opposition groups reacted to the test scores with anger. The Pan-Africanist Congress said it was "appalled" by the results. "We are now reaping the whirlwind of slogans such as 'Liberation before education,' " it said in a statement, referring to a 1976-87 campaign in which anti-apartheid groups urged black students to leave classes and take to the streets. "We cannot run a state with unqualified people. We cannot make our country rich with unskilled labor."

At a public meeting Sunday in Soweto, anguished black parents and teachers demanded a single education department; the opening of schools to all races; greater unity between parents, teachers and students; and better protection from crime and drugs.

Eric Molobi, spokesman for the group, which calls itself the Soweto Education Coordinating Committee, said the education crisis could undermine negotiations between the government and the African National Congress over political reform.

The committee reported that 33 children died last year in Soweto and 204 were injured in township violence. Some 18,000 "loitered in the streets" after dropping out of school. It said schools had been short 229 classrooms and 1,178 teachers, and that up to 92 percent of the students in some classes went without textbooks in at least four subjects. "We are the victims, our future is the victim -- indeed, our whole country is the ultimate victim," said Molobi, who threatened that blacks would seek to "liberate" empty classrooms in better-funded white schools if the government did not address their grievances.

Van der Merwe, considered one of the government's more liberal members, acknowledged that many black schools were overcrowded and understaffed -- "a totally unacceptable situation which we are trying continuously to improve."

He said the question of a single education system -- South Africa has four separate systems, plus others for the nominally independent black "homelands" -- would have to be resolved in negotiations between President Frederik W. de Klerk and the country's black leaders. The issue was "very sensitive," he said, but added, "It is obvious the present system can't be continued indefinitely."

In 1980 the government spent 10 times more on white students than on blacks. Last year, according to van der Merwe, the ratio was 3.6 to 1. "It's still unacceptable," he conceded, "but at least it shows we are putting some money where our mouths are."