The sodomy trial of Malaysian opposition leader Anwar Ibrahim has heard allegations that he sodomised a male aide, leaving traces of DNA.

According to prosecutors the DNA was found in medical tests on the man who is making the allegations.

Mr Anwar has pleaded not guilty.

While he has consistently denied the charges, the court has heard Anwar allegedly demanded sex in a Kuala Lumpur apartment from the 24 year old man who has said he was angry and afraid.

The prosecution has said that Mr Anwar's semen was found in medical tests on the man.

But Mr Anwar has maintained his innocence, with his lawyers claiming the prosecution did not supply them with advanced access to medical evidence, DNA and CCTV tapes, which they have said are crucial in providing a proper defence.

Homosexual acts are illegal in Malaysia and Anwar faces up to 20 years in prison.

Mr Anwar served six years on an earlier conviction, which was subsequently overturned on appeal.

After his release he led the opposition to election gains in 2008.

But Mr Anwar represents a challenge to Prime Minister Najib Razak, whose coalition party has held power for more than 50 years.