Opposition parties have appealed to government not to remove the Scorpions' "sting" in its review of the corruption busting unit's operations.

New National Party media director Adriaan van Jaarsveld said the Scorpions should stay an elite investigation unit, but if possible should fall under the authority of the South African Police Service.

"The Scorpions have more resources available to them than the SAPS, and if these two units are placed together they can become a formidable crime fighting organisation," he said in a statement.

"Currently there are cases that are investigated by both the SAPS and the Scorpions, which is a waste of time, and the conflict of interest only creates more tension," he said.

The NNP welcomed the review of the Scorpions by the public service and administration department.

"We hope, however, that the review will not be overshadowed by the allegations of leaks to the media about the arms deal investigation.

"Since the formation of the Scorpions almost five years ago they have done excellent work, and hopefully the review will highlight their success and make constructive suggestions for the way forward," Van Jaarsveld said.

In a separate statement, Democratic Alliance spokeswoman Sheila Camerer said rather than "splurging taxpayers' money on a politically motivated review of the Scorpions", government should focus on getting the rest of the criminal justice system working.

"It is local policing, prosecution services and the court systems that require a thorough review and overhaul.

"Instead of fighting crime and securing convictions, the ANC leadership has become obsessed with removing the sting of the Scorpions," she said.

The ANC was obsessed with being in control when it should be preoccupied with making sure things work.

"If the latter applied, the government would leave the Scorpions to get on with it and sort out the rest of the criminal justice system," Camerer said.

Safety and Security Minister Charles Nqakula said a review of the Scorpions was about redefining its mandate and not about disbanding it.

The justice department would be asked to draw up a memorandum on the matter that would be discussed by Cabinet.

"It is (the review) on what they do and what the police do - not whether they are closed down or not. That is not the discussion," Nqakula told reporters in Pretoria.

The Scorpions unit, the common name of the Directorate of Special Investigations, which falls under the National Directorate of Public Prosecutions, which in turn reports to the justice ministry, has come under fire in the past week for alleged leaks to the media about its investigations.

These relate to an arms deal probe into Deputy President Jacob Zuma and an investigation into former transport minister Mac Maharaj.

Last week, President Thabo Mbeki said "inherent" tensions between the SAPS and the Scorpions had to be dealt with.

He said the problem was a structural one, and a possible alternative was the Scorpions becoming a specialised police unit.

With acknowledgements to Sapa and the Business Day.