JOHANNESBURG, South Africa (AP) _ Police in the eastern Cape province today lifted nightly curfews and other restrictions imposed under the state of emergency, and a private group said the number of union members detained nationwide had risen to 950.

The Cape province police commissioner, Brig. Ernest Schnetler, gave no reason for lifting the restrictions, which were reimposed last Friday after a regional supreme court overturned them.

The restrictions included: allowing only 200 mourners at funerals in black and mixed-race townships, banning school boycotts and forbidding 52 political organizations to hold meetings.

The court had said Schnetler lacked authority to impose the restrictions, but they were reissued after the government amended the June 12 national emergency decree to give him and other police commissioners such authority.

Schnetler did not explain why he lifted the restrictions today. However, the government has reported virtually no political unrest throughout the country this month.

The Bureau for Information has reported no more than two deaths in unrest on any day this month. It said two black men were killed in the 24-hour period ending at 6 a.m. today. That brings to 217 the number of deaths reported in political violence since the state of emergency began.

The bureau is the only official source of information on events classified as political unrest. Police routinely say they cannot answer questions about violence in their areas, and no security force activity can be reported legally without bureau confirmation.

Journalists also are barred from reporting the names of people held without charge under the state of emergency or from publishing statements deemed subversive.

The Labor Monitoring Group, a private group, said today that 2,730 union members had been detained for varying periods under the state of emergency, and that up to 950 remained in custody, including 350 officials.

The group said it had begun to get reports of detainees from professional unions, such as the Western Cape Teachers Union and the Media Workers' Association of South Africa, a printing industry group. Both are black unions.

According to some estimates, a total of about 10,000 people have been detained. The government has refused to say how many are being held.

Meanwhile, Zulu Chief Mangosuthu Buthelezi said in a speech Wednesday to the Executive Women's Club of Southern Africa, ''There is now every prospect that the state of emergency is likely to become a way of life for some time in our country.

''The failure of the National Party government to recognize that blacks cannot be governed against their will has led to a situation in which a semblance of stability can be maintained only under a state of emergency,'' Buthelezi said.

He reiterated his view, however, that economic sanctions against South Africa were unlikely to hasten the end of apartheid and would only hurt blacks.

Buthelezi, leader of South Africa's 6 million Zulus, the country's largest tribe, is regarded as a moderate who does not believe in fighting apartheid with violence.

He also criticized a government plan to set up an advisory body of blacks. He and almost all black leaders have said such a council must have more than advisory power.

Under apartheid, the 24 million blacks have no voice in national government, which is controlled by the 5 million whites. Whites also control the economy and maintain separate education and health services.

In other developments, Finance Minister Barend du Plessis said Wednesday that sanctions will make it hard for South Africa to repay its foreign debts, and that the government could be forced to impose import controls to retain capital.

''A country that is not permitted to export can obviously not continue to import. Sanctions cut both ways - in the end everyone emerges the loser,'' he said.

Customs agents have begun stalling truck traffic from Zambia and Zimbawe. The two landlocked black-ruled countries, which rely on South African ports to conduct trade, were among six Commonwealth nations that agreed in London this week to impose sanctions against South Africa.

Journalists who went to the Beit Bridge crossing from Zimbabwe to South Africa said today there were only five trucks backed up. Freight agents reported long lines Wednesday evening.