Malaysia's best known opposition politician Anwar Ibrahim was issued with a court summons on Wednesday and his lawyers said they expected him to be formally charged with sodomising a male aide on Thursday.

Anwar, who had hoped to win a parliamentary seat at a by-election set for Aug. 26, denies the allegations and says they are aimed at derailing his political comeback.

Sex between men is illegal in Malaysia and punishable with up to 20 years in jail.

Police confirmed the summons to appear in court but declined to say why, although Anwar's lawyers said they expected him to be charged with sodomy.

"I have information that he will be charged for sodomy tomorrow," Sankara Nair, Anwar's lawyer, told Reuters on Wednesday.

News of the court appearance came an hour after Malaysia's Election Commission set a date for a by-election in a parliamentary constituency held by Anwar's wife which he was expected to win easily.

Anwar, who was barred from parliament in April 1999 after being convicted of corruption, plans to hold a confidence vote in the UMNO-led government in which he said he is confident he can win over 30 government MPs so as to win power.

Anwar has scheduled a press conference for 1500 local time (0700). - Reuters