Cape Town - The controversy over the exclusion of Judge Willem Heath's Special Investigating Unit from the probe into the government's R43 billion arms acquisition programme led to heated exchanges across the floor of the National Assembly on Wednesday.

Justice and Constitutional Development Minister Penuell Maduna said racism seemed to be the motivation for those wanting the unit to be involved, while opposition speakers denied this.

Speaking on the second day of a three-day debate on President Thabo Mbeki's opening-of-Parliament address, Maduna said the unit's exclusion had nothing to do with politics, but was based on sound legal and constitutional principles.

The Constitutional Court had said - in a ruling in November last year - that Mbeki could not issue a proclamation for the unit to become involved based on malpractice "might" having been involved.

Maduna said the chairman of the standing committee on public accounts, Gavin Woods, had "admitted" in a newspaper interview at the weekend there was no evidence of corruption in the arms deal, and all allegations were highly speculative.

Maduna said racism seemed to be the motivation for those wanting the Heath unit to become involved, as black empowerment groups were involved in arms deal contracts.

The days of white supremacy and parliamentary sovereignty were over - with the Constitution being supreme - and Parliament could not order the president to issue a proclamation for the Heath unit's involvement, he said.

Pan Africanist Congress president Stanley Mogoba said the apartheid trap door, which the liberation forces had closed, had been brought back by the arms deal.

"Why, one asks, is it so difficult to use all the investigation tools at our disposal - the four commissions - to clear up this mess?"

Mogoba said to make allegations of corruption was not a crime, "but to duck and dive is suspicious in the extreme".

What was critical was not the personality or colour of Heath; people needed to be reminded that a black president (Nelson Mandela) had appointed him as head of the unit, Magoba said.

"The issue here is greater than Judge Heath. We have to fight corruption in a transparent and convincing way. Our courts and history will deliver the final verdict."

Democratic Alliance Chief Whip Douglas Gibson said ANC MP Vincent Smith had - in a television programme on Tuesday night - tried to present the controversy surrounding the standing committee on public account's role in the issue as a "racial matter".

"He does not understand that it is a matter of good governance, of openness and accountability."

Trade and Industry Minister Alec Erwin said the probe was being conducted by South Africa's constitutional and legal structures, and government was giving all the assistance it could.

The investigation would come up with a result.

Damage was being done to South Africa's image by those spreading perceptions they had no confidence in the instruments of state, Erwin said.

Mbeki is to reply to the debate on Thursday afternoon. 

With acknowledgement to Sapa and News24.