The Pretoria High Court sentenced 69-year-old Daniel Geiges to 13 years in prison but suspended the sentence for five years in a plea bargain, SAPA said.

That means Geiges is essentially under probation for five years and any violations would land him in jail for the 13-year period. Geiges agreed to cooperate with international nuclear authorities.

Geiges admitted guilt and said he had been involved in the illegal import, export and manufacture of material related to nuclear equipment 10 years ago.

A German engineer who was charged along with Geiges, Gerhard Wisser, was in September given a suspended 18-year jail sentence by a South African court after also pleading guilty to involvement in the nuclear smuggling ring.

A third man arrested in the case, Johan Meyer, turned state witness.

Wisser was accused of having ties to a network run by Abdul Qadeer Khan, the disgraced father of Pakistan's atomic bomb who has admitted giving nuclear secrets to nations under international embargo.

The case was part of an international effort to crack what prosecutors said was a trade network that helped Libya, North Korea and Iran skirt sanctions in their quest for nuclear technology.

South Africa, which voluntarily dismantled its own nuclear weapons programme before the end of the apartheid era in 1994, was among 20 countries named by the United Nations' atomic agency as recipients of Khan's atomic secrets.