The elite crime-busting unit, the Scorpions, has refused to confirm or deny whether it is investigating Deputy President Jacob Zuma.

Despite publication of a Scorpions affidavit in the Durban High Court last year, which points to a probe into Zuma over allegations that he was involved in bribery relating to the government's multibillion-rand arms deal, the unit has insisted that it does not name suspects.

"We have never confirmed or denied we are investigating anyone, including the deputy president," said a Scorpions spokesperson.

Zuma has reportedly been irritated that the Scorpions has not questioned him, nor denied the investigation.

President Thabo Mbeki has defended Zuma's right to stay on as deputy president as long as no charges were laid against him.

"If there is some offence which the deputy president has committed, he will be charged in the same way the chief whip has been charged," said Mbeki, referring to the decision by former African National Congress chief whip Tony Yengeni to stand down after he was arrested on charges relating to the arms deal.

With acknowledgements to Jeremy Michaels and The Star.