An investigation into allegations of the “imminent arrest” of Public Protector Thuli Madonsela is underway, says Police Minister Nathi Mthethwa.

“It appears someone with malicious intent is out there spearheading a campaign to discredit the SAPS and we shall not take this lightly. I have instructed an immediate investigation into these malicious lies and whoever is responsible must be brought to book,” said the minister on Thursday.

Mthethwa said he finds such allegations not only damaging to the South African Police Service (SAPS) image, but also lacking in substantive backing.

“Some people are continuously peddling these negative campaigns, which portray the Public Protector as a victim in the eyes of society and the department as the proponent of this victimisation. This must stop and stop now,” he said.

This comes as media reports emerged that Madonsela is to be arrested on fraud and corruption charges. The claims go back three years to when she was a full-time Commissioner of the South African Law Reform Commission (SALRC). Reports allege that Madonsela's company did work for the SALRC and was paid R1.8-million.

Mthethwa urged the public, particularly Independent Newspapers, to provide evidence or information regarding the matter. Independent Newspapers on Wednesday published front page allegations of her arrest.

“The minister was and is not aware of this alleged pending arrest of Ms Madonsela, hence he proactively phoned her yesterday to get clarity on these allegations,” said his department.

“I only learnt about this purported and imminent arrest during a live interview with SAfm following my visit to the Eastern Cape in addressing the issue of mob justice. I verified with the National Commissioner of Police and he was also unaware of any pending arrest. In addition, I personally phoned the Public Protector and she informed me that the information she had seen was through the media,” explained the minister.

At a press conference yesterday, Madonsela dismissed the allegations calling them "baseless, without truth and malicious."