Public Protector Thuli Madonsela wants National Police Commissioner General Bheki Cele to explain why two policemen arrived at her office asking for documents relating to her recent probe into his involvement in a R500 million improper lease agreement, her office said on Friday.

"The Public Protector has written to General Bheki Cele just seeking clarity on the purpose of the visit," said Madonsela's spokeswoman Kgalalelo Masibi.

"The Public Protector is worried because she felt she could have been informed in advance. She also could not decipher why she features in [an] internal investigation in the [police]."

Masibi said that Cele also called Madonsela on Thursday to apologise for the incident, which her office described as a visit, not a raid as there was no search and staff did not feel intimidated.

"He phoned the Public Protector and said that he did not sanction the visit and that the matter is going to be investigated and that he apologises for the incident," said Masibi.

She said two policemen, a Colonel Maluleka and a Captain Nkuta, arrived at the offices [on Wednesday], on the instructions of a Colonel Heine.

Without official papers backing up their request, they sought a document referred to in a Sunday Times report last week and wanted to know if it had formed part of the protector's findings regarding a police lease probe.

Madonsela could not understand why the police needed the document, because it was given to her office by the police themselves during her investigation.

"It is [the police] that provided the Public Protector with those documents. They were actually asking for information which they themselves had. It was their own documents."

Her report was on an investigation into a R500-million lease agreement for new police headquarters in Pretoria.

The Sunday Times had alleged that Cele had signed a lease agreement for the building with businessperson Roux Shabangu without it being put out to tender.

Last month, Madonsela concluded that Cele was implicated in unlawful conduct and maladministration as the accounting officer for the police, even though he was not directly involved in the final lease agreement.

She recommended that Cabinet get an explanation from Public Works Minister Gwen Mahlangu-Nkabinde on why she decided to continue with the lease despite getting legal opinion advising against it.

The Sunday Times reported on Sunday that there was a document which showed that Cele allegedly personally authorised funds for the lease agreement.

Cele responded to the Public Protector's findings by questioning her authority to pronounce him guilty of improper conduct.

He said that the Special Investigating Unit had no right to have been part of her investigation. He suggested that a subordinate Hamilton Hlela may have been responsible, and that he had not known about the final agreement.

During the police visit on Wednesday, Madonsela decided to give the police a list of the documents which formed part of the investigation, but not the documents themselves, said Masibi.

Comment was not immediately available from Police Minister Nathi Mthethwa's spokesperson, but police spokesperson Major General Nonkululeko Mbatha said on Friday that "processes" were underway regarding the visit by the counter intelligence officials.

She would not elaborate.

She and McIntosh Polela, who usually does media comment for the Hawks, but said he was speaking for the police, issued a joint statement on Thursday.

In it, they said: "The SAPS management strongly condemns an act of alleged invasion of the office of the Public Protector by members from counter intelligence.

"The members acted outside their mandate hence appropriate action is being instituted accordingly."

Opposition parties have criticised the incident, with some saying Cele should step down.

Meanwhile, Madonsela is still waiting to meet with Justice Minister Jeff Radebe and Cabinet secretary Cassius Lubisi to discuss the report before the government announces its position on the matter.

Justice spokesperson Tlali Tlali said the matter of discussing the report was being given "the priority it deserves" and the availability of everyone required to be at the meeting was being checked.

Once a date was decided the department would probably announce it and after meeting Madonsela, it may have a media briefing.