JOHANNESBURG, OCT. 15 -- The South African government imposed strict new controls on universities tonight, threatening to cut off state subsidies unless antiapartheid protests and other demonstrations on campuses are curbed.

University heads immediately charged that academic freedom was being curtailed and that the measures will encroach on the autonomy of higher education.

The minister for national education, F.W. de Klerk, said the government would compel universities to enforce stricter campus discipline or face a cutoff of state funds, which can account for 70 to 80 percent of university operating costs.

De Klerk said that the universities will be expected to adopt "all reasonable steps" to prevent class boycotts, support for civil disobedience campaigns and political movements banned by security laws and decrees.

He said the government had tried to persuade universities to enforce stricter discipline, but there had been no indication that the incidence of "unacceptable occurrences" had declined.

The responsibility for disciplining staff and students who participate in or encourage "revolutionary" protest will rest with the universities, government officials said.

The new regulations also are designed to curtail unlawful strikes and the use of university notice boards and stationery to promote banned organizations. Violations and the results of disciplinary hearings must be reported within 10 days of an incident.

Class boycotts to protest the system of racial segregation known as apartheid have closed a number of black universities for weeks at a time during the last three years. White universities, most notably the University of Cape Town and the University of the Witwatersrand in Johannesburg, have been disrupted by antigovernment demonstrations.

Campus protest in South Africa is a sporadic and relatively low-key phenomenon, limited mainly to the English-speaking universities.

Protests were the subject of a national debate in August after several attacks by militant students on prominent politicians on the Cape Town and Witwatersrand campuses.

Among those prevented from speaking by demonstrators -- most of them black -- were Denis Worrall, the former South African ambassador to Great Britain; Helen Suzman, the veteran member of Parliament from the opposition Progressive Federal Party; moderate Zulu leader Mangosuthu Gatsha Buthelezi, and Conor Cruise O'Brien, the Irish diplomat and liberal philosopher.

Following those incidents, which were widely criticized by liberal as well as conservative whites, the government said that subsidy conditions were necessary to protect freedom of speech.

The vice chancellor of the University of Cape Town, Stuart Saunders, said today that university lawyers would be consulted about the possibility of a court challenge to the new subsidy conditions.

Saunders, in a statement issued in anticipation of the new measures, said it was "fundamentally wrong and counterproductive" to place conditions on state funding of higher education.

"It is fundamentally wrong because it seriously encroaches upon the autonomy of the university and it is counterproductive because it undermines the authority of the university council and the executive officers," Saunders said.

He added, "At the University of Cape Town we will continue to conduct our affairs properly as in the past and we will maintain the high standards we have set for ourselves. We do not accept the need for these additional measures."

The chairman of Witwatersrand's Academic Staff Association, Peter Randall, said when the restrictions were proposed last month that "they just about snuff out any activity that Pretoria thinks is politically unacceptable."

De Klerk said tonight, "Our aim is not to encroach upon the autonomy of the universities. I would like to stress that the conditions and procedures are composed in such a way that the managerial autonomy of the universities, and the academic freedom of students {and} staff as it has developed historically, will not be substantially affected."