The country's security establishment is due for a shake-up this week.

Several senior government sources said the drama around Police Commissioner Jackie Selebi and suspended National Director of Public Prosecutions Vusi Pikoli would draw in others in the National Prosecuting Authority and South African Police Service.

They expect key figures in both the NPA and the SAPS to be shunted sideways now that Pikoli, suspended by President Thabo Mbeki late last month, faces an inquiry into his fitness for office.

Selebi also has a tense two weeks ahead as top legal minds help the acting NPA head, Mokotedi Mpshe, to decide whether Selebi should be prosecuted for crimes ranging from defeating the ends of justice to racketeering.

This comes after a warrant for his arrest was withdrawn late last week because Mpshe is to review his case.

ANC ally Cosatu has described the situation as a "serious crisis", and top government officials say the timing could not be worse in the heat of the ANC succession race and ahead of the party's crucial December conference.

Several senior cabinet ministers are understood to want a better briefing about what's really going on. They apparently believe the situation is so poisoned that the top echelons of the SAPS and the NPA need to be reshaped.

"Expect a shake-up, but not a purge," a senior security-linked official said.

There is no list yet of who will be affected, as much depends on the outcome of the Mpshe's review and the Ginwala inquiry.

However, the heat appears to be on the Scorpions' head, advocate Leonard McCarthy. As Scorpions chief, McCarthy bears ultimate responsibility for a range of high-profile probes from the arms deal to Travelgate. He is a proponent of keeping the NPA independent, especially from the SAPS.

The head of the Gauteng Scorpions, Gerrie Nel, along with chief investigator Andrew Leask, are also under pressure.

On the SAPS side, there are concerns that Selebi's deputy, Andre Pruis, has too much power, given Selebi's Interpol responsibilities.

Then there is speculation that top prosecutor Anton Ackermann might be shifted from his post. Ackermann is the head of the Priority Crimes Litigation Unit and special director of public prosecutions, which deals with crimes against the state.

Ackermann's unit also oversees the NPA's investigations and prosecutions related to the Truth and Reconciliation Commission.

His credibility hangs in the balance over the authenticity of a letter he allegedly wrote to the police, demanding further investigation into 37 ANC leaders, including Mbeki. The 37 failed in trying to motivate for a collective amnesty from the TRC, but in 2004 Bulelani Ngcuka, the NPA boss at the time, decided not to prosecute them.

The NPA said last month that the letter had been forged. Sources say the police have a copy of the letter, which they insist is an original.

The Scorpions have launched an internal investigation into the letter's authenticity.

Any shake-up is likely to trigger another round of exits from the NPA, with skilled staff such as legal experts and forensic analysts heading for the private sector.

The NPA's annual report, released last week, highlighted low staff morale. There are up to 40% unfilled posts.

With acknowledgements to Chiara Carter, Christelle Terreblanche and The Star.