The defence minister, Samuel Schmid, says the South African government will not be asked to assist in a Swiss probe into alleged apartheid-era links between the two countries' secret services. He added that the findings would not be made public.
Schmid told parliament on Monday there were no plans to seek help from the South African government. He said the nature of the probe meant it was not necessary to request access to documents in South Africa or to question South African witnesses.
The probe is trying to establish whether Peter Regli, the former head of Switzerland's military intelligence service was involved in criminal activities of the South African secret service, and if any documents relating to Swiss-South African intelligence cooperation are missing.
Wouter Basson, the director of South Africa's covert chemical weapons programme during the apartheid era, claimed Regli helped him to acquire 500 kilograms of an illegal drug, Mandrax, from Russia in 1992. He also said he was transported in helicopters belonging to the Swiss air force during his visits to Switzerland.
Basson made the allegations at court hearing in South Africa where he is on trial for murder, attempted murder and fraud. He reportedly indicated he was willing to testify in Switzerland, if he was granted immunity in that country.
Regli denies allegations
Regli, who is now retired, has repeatedly denied any connections between the Swiss secret service and the covert South African weapons programme while he was director.
He dismissed Basson's allegations as "unsubstantiated slander" and "a sweeping defence by a criminal". In 1999 a parliamentary inquiry cleared Regli of involvement in South Africa's weapons programme.
Regli maintained the contacts between the Swiss and South African secret services were "purely of an informative nature".
The defence minister also said the result of the investigation, launched last month and due to conclude by the end of October, would not be made public. But the ministry earlier said the probe could be extended if there were any suspicions remaining.
swissinfo with agencies