The parliamentary opposition leader, Lim Kit Sang, said Mr Mohtar had failed to take effective action for five months after Mr Anwar appeared in court with a black eye.

Mr Mohtar is leading the prosecution of Mr Anwar on charges of corruption and illegal sexual practices.

The former police chief, Tan Sri Rahim Noor, resigned his position in January after an inquiry by Malaysia's attorney general found that Mr Anwar's injuries were caused whilst he was in police custody.

Fit of anger

Tan Sri Rahim Noor says he hit Mr Anwar in a fit of rage

Earlier this week, Mr Rahim Noor confessed to the assault during an independent inquiry which concluded its hearings on Thursday.

He said he had acted in a fit of anger of slapping Mr Anwar after he allegedly insulted him.

Mr Anwar told the inquiry that he was blindfolded and handcuffed during the assault and had said nothing before he was attacked.

A report presented to the inquiry last week by government doctors said Mr Anwar was "hit by a blunt object at least four times on the head and neck and slapped at least twice." It said his injuries were in "potentially lethal" places.

Legal action

Wan Azizah says she wants action taken against the former police chief

On Thursday the former police chief issued an apology through his lawyer to Mr Anwar and his family saying he "regretted his actions".

Mr Anwar's wife, Wan Azizah Ismail, said on Friday that she accepted the apology but wanted legal action to proceed against Mr Rahim Noor.

"I accept graciously the apology, even though through the counsel, but the due process of the law has to take place," she said.