With newspapers here speculating that a Namibian cease-fire may be only days away, the Defense Force headquarters in Pretoria announced tonight the heaviest South African death toll in the 16 years of bush war for the disputed territory.

A communique said 15 men were killed when a helicopter was shot down in southern Angola while ferrying troops in a follow-up operation against insurgents of the Southwest Africa People's Organization.

Defense Force Gen. Constand Viljoen said 201 SWAPO insurgents were killed in the operation, and several similar ones were carried out in recent weeks. He did not say exactly where the helicopter was shot down nor when.

Earlier, the Angolan news agency Angop quoted SWAPO claims to have destroyed a South African military base in northeastern Namibia last Wednesday, killing 30 South African soldiers. South Africa denied the report.

The press reports on the impending cease-fire, which is to lead to independence of Namibia, cautioned that difficulties again could delay implementation of an initiative by Western nations.

In a separate development, a Supreme Court judge in Pretoria dismissed an application by the outspoken black opponent of apartheid, Anglican Bishop Desmond Tutu, for the return of his passport, news agencies reported.

[Tutu's passport was withdrawn in April 1981, after he returned from a speaking tour of Europe and the United States.]