Police moved today to silence many leading antiapartheid groups in Cape Town by prohibiting the press from quoting any of their officials and forbidding them to publish any materials themselves.

Among 119 organizations affected by the gag order are the United Democratic Front, a coalition of antiapartheid groups with 2 million members nationwide; the Congress of South African Trade Unions, the nation's largest labor federation; the black-consciousness Azanian People's Organization and the Detainees' Parents Support Committee.

Although the order applies only in the six magisterial districts in and around Cape Town, it was seen as a model for similar moves by police elsewhere in the country. The apparent intent of the order is not only to silence much of the present criticism of the government but to further weaken organizations already hit hard by widespread detentions of political activists under the state of emergency.

In another move, police relaxed one restriction on journalists by allowing them to enter black townships and report on any events there that do not involve unrest and that are not related to the activities of the police and Army. On Monday, reporters had been completely barred from all the segregated black townships.

The government's Bureau of Information, the sole authorized source of news on civil unrest, reported that no one was killed in political violence during the 24 hours ending at daybreak Saturday. Only scattered incidents of unrest, mostly in black townships east of Johannesburg, were reported, according to the government.

This was the first day in many weeks that no unrest-related deaths were reported, and the government cited it as evidence that its tough measures are restoring law and order. Before Saturday, a total of 54 persons had been reported killed in the period after the current state of emergency was declared June 12.

The police move was denounced in Parliament by Peter Gastrow of the Progressive Federal Party, a liberal white opposition group. Gastrow accused the government of trying to "bluff us" into believing that the situation is improving. The new curbs, if they work, will only give whites "a false sense of relative stability," he said.