A top-level meeting between the Hefer Commission and lawyers for the country's intelligence units has reached stalemate.

The intelligence units have refused to provide information requested by Mo Shaik and Mac Maharaj, National Director of Public Prosecutions Bulelani Ngcuka's principal accusers.

The National Intelligence Agency and the South African Secret Service on Monday night insisted that they would not provide information in their possession to the commission, as this could compromise their intelligence-gathering strategies.

Members of the commission have spent the past two days in consultation with lawyers for the intelligence agencies and the police about whether several of their members would be able to give evidence.

It was agreed, however, that George Bizos SC, acting on behalf of the intelligence units, would appear before retired judge Joos Hefer to explain the positions of the units on Friday, according to the commission's spokesperson, John Bacon.

"Bizos will make a full presentation and disclose the details relating to their position," Bacon said.

The Hefer Commission, established by President Thabo Mbeki, is investigating allegations that Ngcuka had served as an apartheid-era spy - either as agent RS452 or under any other codename - and whether he had abused his office by investigating people who had probed him under the African National Congress's Project Bible in the 1980s.

A City Press report alleged that Ngcuka was investigated by the ANC on suspicion that he was a spy - but it made no mention of what the findings of the ANC investigation were.

Bacon disclosed that advocate Glen Goosen, a former member of the Port Elizabeth Action Committee, would take the stand on Thursday to give evidence on what he knew about agent RS452 or any information relating to the commission's work.

Wednesday's proceedings are set to start with Judge Hefer giving his reasons for forcing former Sunday Times journalist Ranjeni Munusamy to give evidence.

Meanwhile, former police commissioner George Fivaz has been subpoenaed to give evidence at the commission.

It is believed that Fivaz and his legal team, headed by advocate Pete Mihalik, will soon be on their way to the commission in Bloemfontein.

Fivaz said during a radio interview last month that he would have known if Ngcuka was a spy.

With acknowledgements to Makhudu Sefara, Estelle Ellis and The Star.