KUALA LUMPUR: Sacked former deputy prime minister Anwar Ibrahim could be arrested soon, Malaysia's police chief has suggested.

Inspector-General Rahim Noor said police had "strong evidence" that Mr Anwar had tried to interfere with their investigation into a book, 50 Reasons Why Anwar Cannot be Prime Minister, which contained allegations of illegal sexual behaviour against Mr Ibrahim.

Mr Rahim said the evidence of this interference, which allegedly took place when Mr Anwar was deputy prime minister, would be "produced in court".

Mr Rahim also said Mr Anwar had "exceeded the limits" by comparing the Malaysian police to Israeli intelligence agency Mossad because they arrested his former aides.

As part of their investigations into the allegations against Mr Anwar, police have arrested or questioned people closely associated with him.

They include a tennis partner, his adopted brother, a speech writer and a former senior private secretary at the Ministry of Finance. Mr Anwar was also finance minister before his sacking.

Mr Anwar said another aide had been detained yesterday. His former private secretary, Mohamed Azmin Ali, had been held after agreeing to present himself at federal police headquarters, Mr Anwar said.

Mr Anwar said he expected to be arrested when the Commonwealth Games ended on September 21 and to be charged with 21 offences, including treason for allegedly selling state secrets.

Mr Anwar said his supporters had been contacted by prostitutes who said authorities had threatened them with detention if they did not give evidence against him.

Meanwhile, a leading MP for the United Malays National Organisation (UMNO), the dominant government party, has expressed concern that people would "be confused" over the expulsion of Mr Anwar from the party for alleged moral misconduct in view of his background as an advocate of Islamic values.

Jamaluddin Jarjis, president the UMNO Backbenchers Club, said the expulsion had to be explained so Malaysians could differentiate "between Anwar's personal issues and other issues".

He said MPs of all ruling National Front coalition parties agreed to inform their constituents of the "real issues" behind Mr Anwar's dismissal from UMNO and the Government after Prime Minister Mahathir Mohamad briefed them.

The public has yet to be given any convincing evidence of Mr Anwar's impropriety since Dr Mahathir announced a week ago that his former deputy's character did not qualify him to be a leader of an Islamic country like Malaysia.

Dr Mahathir implied that he believed allegations contained in court affidavits that Mr Anwar engaged in sexual relations with a man and a number of women.

Mr Anwar claims he is the victim of a high-level conspiracy.