Greg Barrow reports from the court

The magistrate called his refusal "unlawful, intentional and without sufficient cause".

His sentence - which could be either a fine or a prison sentence - is expected to be announced shortly.

Mr Botha, 82, was summoned before the commission to answer allegations that he was at the head of a state-sponsored strategy to silence and harass anti-apartheid activists while in office.

Former minister Adriaan Vlok: said Botha ordered church bombing

Former ministers and security force personnel testifying before the Truth Commission directly implicated him in bombings and accused him of authorising the murder and torture of activists.

He has consistently denied these charges, maintaining that the Truth Commission was a witch-hunt against white Afrikaners, dominated by supporters of the now-ruling African National Congress.

Our South Africa Correspondent, Greg Barrow, says that the former president has undermined the credibility of the Truth Commission, and exposed its weaknesses.

He says whatever the sentence, it will be a hollow victory for the Truth Commission, which has now lost its power to bring witnesses before court and will never hear directly from the man who headed the South African Government during what was known as the "total onslaught" period of apartheid.

Cost of trial

Mr Botha has appeared in court regularly since January to defend his defiance of three orders to testify before the Truth Commission.

Questions will inevitably be raised about the expense of the trial.

Every day that Mr Botha has arrived in court, a huge security operation has moved into gear. The courthouse has been surrounded by three tiers of razor wire and extra armed police have been deployed outside.

Conservative estimates put the final cost at more than $300,000.