The paper quoted an affidavit filed on Monday by Mokotedi Mpshe, the acting head of the National Prosecuting Authority (NPA) in its case against National Police Commissioner Jackie Selebi.

"The president himself has been kept fully informed of both the fact of the investigation against Selebi and the nature of the allegations against him," the Star quoted Mpshe as saying in the filing.

The affidavit also said NPA head Vusi Pikoli, suspended by Mbeki last year after requesting an arrest warrant for Selebi, repeatedly informed senior ministers and other officials of the accusations against the police chief in 2006 and 2007.

The affidavit may cast doubts on Mbeki's assertion he did not know of the graft allegations hanging over Selebi, a long-standing ally of the president.

There was no immediate comment from Mbeki's office or the NPA on the Star report.

Selebi faces charges of corruption, fraud, money-laundering and racketeering in connection with his ties to Glenn Agliotti, a convicted drug smuggler accused of playing a role in the 2005 murder of a South African mining magnate.

Prosecutors say Selebi received payments from Agliotti.

Selebi, who is due to appear before a magistrate on June 26, has denied the charges and is now on extended leave from his position. He also has resigned as president of international crime-fighting agency Interpol.

The police chief is among a number of high-profile officials ensnared in corruption investigations, which have drawn accusations of high-level political manipulation and stoked investor worries about political instability.

Opposition parties and Mbeki's enemies in the ruling African National Congress (ANC) have accused the president of protecting Selebi from prosecution for months last year, even though a warrant for the police chief's arrest had been issued.

The case has rattled the political establishment and threatens to further destabilise Mbeki's government, which has come under pressure since the president lost the leadership of the ANC to rival Jacob Zuma in a bitter contest in December.

Zuma's supporters are among those who have accused Mbeki and his senior aides of political meddling in the justice system.

Now the frontrunner to succeed Mbeki when he leaves office in 2009, Zuma faces trial in August on separate charges of corruption, fraud, money-laundering and racketeering laid against him shortly after he beat Mbeki.