Pretoria - President Thabo Mbeki would consider appointing a special investigating unit (SIU) if this was needed to probe South Africa's R43 billion arms deal, the presidency said on Thursday.

"There is absolutely no problem with considering the involvement of an SIU at an appropriate time," presidential legal advisor Mojanku Gumbi told reporters in Pretoria.

Political observers have interpreted the move as a bid to appease public concern following Mbeki's decision to exclude the unit headed by Judge Willem Heath from the probe.

In another new development on Friday, SABC news reported that the ANC has called on the government to probe Judge Heath following the interception of letter from Pan Africanist Congress MP Patricia de Lille to Judge Heath calling on him not to supply information and documents to President Thabo Mbeki as requested.

Friday is also the deadline given by De Lille to Mbeki for him to supply reasons why Judge Heath was excluded from the arms deal probe.

Mbeki's lawyers confirmed on Thursday that the information would be supplied but warned that "it could take some time."

Discussing what she regarded as " an appropriate time" for the establishment of a new special unit, Gumbi said this would be after the amendment of the Act governing SIUs and provided that prima facie evidence of wrongdoing in the arms deal had emerged by that stage.

"If the investigation is still on and there is a need for that kind of power and skill, the president will certainly consider that."

Gumbi reiterated that sufficient information was required for a proclamation to be issued that would enable the appointment of an SIU.

She and Director-General in the Presidency Frank Chikane were briefing reporters about the government's stance on demands for a multi-agency probe into allegations of corruption in the arms deal.

Parliament's watchdog public accounts committee last year called for such an inquiry to be conducted by the SIU headed by Judge Willem Heath, the Auditor-General, the Public Protector, and the Investigating Directorate: Serious Economic Offences.

Mbeki on January 19 announced that the Heath unit would be excluded from the investigation.

In a televised address he cited a Constitutional Court ruling that it was unconstitutional for a judge to head the unit. Mbeki added there was not sufficient information to justify a proclamation for the unit to conduct a probe.

Mbeki quoted two senior advocates, Heath unit investigator Jan Lubbe, and Western Cape Director of Prosecutions Frank Kahn, to support his contention that a proclamation was not justified.

They agreed that there was no prima facie evidence that a criminal offence had been committed in the arms deal, Mbeki said.

It has since emerged that both advocates also told Mbeki that they agreed with the public accounts committee that an investigation by an SIU into the arms deal was warranted.

This was not mentioned by Mbeki in his televised address, prompting accusations that he had misled the public.

Chikane and Gumbi on Thursday denied these assertions, saying Mbeki had referred to the two advocates only with regard to the availability of prima facie evidence.

Gumbi contended that the two advocates had also foreseen a legal problem with the appointment of an SIU in view of the Constitutional Court ruling.

Hence their proposal that an acting judge be appointed to head the unit until legislation was amended to accommodate the Constitutional Court ruling, Gumbi said.

The two advocates argued that an acting judge could revert to his personal status once a new SIU Act was in place. This would ensure continuity should the unit be involved in the probe from the start, they said.

Gumbi on Thursday cited this proposal as evidence that the two advocates also recognised there was a legal problem with the appointment of an SIU.

Chikane rejected criticism that Mbeki had not applied his mind to the recommendation of the two advocates.

"I'm saying he did apply his mind, because I was there," he said.

Chikane confirmed that a preliminary investigation by the three other investigation agencies was underway to determine whether prima facie evidence of wrongdoing existed.

The result of this inquiry would determine government's further course of action, Chikane said.

Cabinet on Wednesday approved a draft Bill providing for an individual other than a judge to head the SIU. It would be tabled in Parliament as soon as possible, the Justice Ministry said. 

With acknowledgement to News24.