Scientist Johan Koekemoer told the commission that he made more than 900kg of Ecstasy on behalf of the military shortly before the end of apartheid.

Mr Koekemoer said he had been led to believe that the drug - with a street value of $200 million - would be used by the military to incapacitate its enemies.

But he said he made Ecstasy reluctantly, as he was not convinced of its effectiveness.

Chemical warfare

Mr Koekemoer was giving evidence on the second day of a week-long inquiry into the former government's chemical and biological warfare programme.

Truth Commission chairman Desmond Tutu at last week's hearings

The TRC, chaired by Archbishop Desmond Tutu, is the official body set up to investigate human rights abuses under apartheid.

The present round of TRC hearings, which will continue throughout the week, are expected to reveal details of an extensive chemical and biological warfare capability which was used during the 1980s to silence opponents of the apartheid government.

The Commission has heard that there were plans to poison medication given to President Mandela while he was still in prison

Evidence of the existence of the Ecstasy scheme first came to light in court last year during the trial of chemical weapons expert Dr Wouter Basson.

Mandela - plans to poison him in prison

In his testimony, Dr Koekemoer also confirmed his laboratory had experimented on other chemical and nerve agents, including the use of extracts of cannabis as a means of riot control.

Further details were kept from public scrutiny after the present government succeeded in an application for the trial to be conducted in camera, in order to preserve the security of sensitive information.

However, the government failed in its attempt to have the present TRC hearings conducted in secret.

Poisoned umbrellas

Evidence already collected by the commission has already uncovered the use of poison-tipped umbrellas, chemical irritants which were sprayed on people's clothes and viral agents which were used to infect bottles of beer and soft drinks.

The objective appeared to be to kill or maim government opponents.

The TRC is trying to establish the extent of the chemical and biological warfare programme to discover whether it was sanctions by the apartheid government or if it was the work of renegade groups within the security services.

It also wants to find out whether the apartheid government had a more advanced programme for biological and chemical weapons.

The South African parliament today also voted to extend the lifespan of the Truth and Reconciliation until the end of July.