"Enquiries are being made into the activities of some companies and individuals, who may have been involved," said Abdul Minty, who chairs South Africa's Council for the Non-Proliferation of Weapons of Mass Destruction.

"In this connection an arrest has been effected today and there has been a recovery of items alleged to have been used in the contraventions," he said in a statement.

Minty said the investigations were being held "by South African authorities ... their counterparts in other countries as well as the (nuclear watchdog) International Atomic Energy Agency (IAEA)."

The statement however, did not give further information.

Foreign Affairs spokesman Ronnie Mamoepa also declined to give information saying "more will be known by tomorrow (Friday)."

In late August, a German man suspected of trying to help Libya develop nuclear weapons appeared in court in Karlsruhe, Germany.

German prosecutors said the man, only identified as Gerhard W., 65, worked as a mediator in obtaining an order for a South African company to make and supply aluminium tubing to be used in a uranium enrichment plant.

It was not clear if the court appearance in Germany was related to Thursday's arrest.

American investigators earlier this year also probed an illegal nuclear technology network in South Africa which a Cape Town man was believed to be involved in.

Since 1994, South Africa has adopted a strict policy of disarmament and the proliferation of nuclear weapons and the ability to build them.

The country's foray into the world of nuclear weapons started in 1948, the same year the white apartheid government came to power, with the establishment of the Atomic Energy Board (AEB).

On March 24 1993, only a year before the country's first ever democratic elections, which would put the ruling African National Congress in power, former South African President FW (Frederik) de Klerk, revealed the country had developed a "limited nuclear deterrent" during the 1970s and 1980s.

The country had seven nuclear weapons, but said the Klerk at the time, dismantled them. He invited the IAEA, headed by former chief UN weapons inspector in Iraq, Hans Blix, to conduct inspections.

Early last year, Blix praised highly what he called "the South African model of co-operation" and at the time, urged Iraq to adopt it.