South African Police Minister Jimmy Kruger launched an official complaint yesterday against the Rand Daily Mail after the newspaper inferentially accused him of lying about the death of black activist Steve Biko.

The newspaper said Biko, who died in police custody Sept. 12, suffered brain damage and was not on a hunger and thirst strike as the South African government had alleged.

Quoting physicians who examined Biko beofe his death and sources close to the black leader, the Mail denied that Biko had lost weight during a reported seven-day hunger strike that preceded his death.

Biko's death provoked an outcry both inside South Africa and abroad.It has become the focus of antigovernment protest by black and white liberals in this white minority-ruled country.

The results of a Sept. 13 autopsy, performed by state pathologists in the presence of physicians representing Biko's family, have not yet been published.

The report was originally scheduled for completion next Monday, but chief state pathologist Johann Loubser said yesterday that he was calling in "two specialist researchers" to conduct more tests and "this may still take more time."

As a reslut of Kruger's complaint, the Mail will be given a hearing by the Press Council, a disciplinary body set up earlier this year as a self-censorship group after government attempts to censor some press reports of a political nature.

In another development, the Rhodesian government, under criticism for expelling missionaries suspected of security offenses instead of putting them on trial, decreed that the press may not report on deportations without permission. The decree does not prevent foreign correspondents from reporting on deportations, but foreign news reports on such developments may no longer be published in Rhodesia.