Former national police commissioner Jackie Selebi has warned he will drop more bombshells as his trial unfolds.

In his plea explanation on Monday, Selebi accused former National Prosecuting Auhority heads Bulelani Ngcuka and Vusi Pikoli of being corrupt. He told the South Gauteng High Court they were behind a conspiracy against him.

Selebi has pleaded not guilty to charges of corruption and defeating the ends of justice.

Leaving court through a scrum of cameras the former head of Interpol said he was pleased that he could finally enter his plea of not guilty.

"I am glad it is starting," says Selebi.

He warned that more bombshells could be expected.

He made startling revelations that Ngcuka and Vusi are themselves implicated in corruption.

Selebi alleges that Ngcuka tried to solicit a bribe from the lawyer of former Hyundai head Billy Rautenbach and that Pikoli's wife received shares from one of Brett Kebble's companies, Simmer and Jack Limited.

The man in the dock claims that when he instituted an investigation into the duo the Scorpions began a campaign to discredit him as national police commissioner.

Ngcuka and Pikoli have not taken Selebi's claims lying down. Each of them has issued a statement denying his claims.