Australian Prime Minister Scott Morrison on Monday stood by an unnamed Cabinet member after an allegation that a senior minister in his Cabinet raped a 16-year-old girl more than 30 years ago.

Morrison rejected calls to suspend the minister, saying the unnamed official "vigorously denied" the allegations, which have now been referred to police.

The prime minister, who is already under mounting pressure to tackle what has been described as sexist culture within Australian politics, said the minister was innocent until proven guilty. The identity of the minister has not been released owing to Australia's standards on defamation. Sixteen members of Morrison's 22-minister Cabinet are men. 

'Matter for the police'

"Allegations of criminal conduct should be dealt with by competent and authorized agencies," Morrison said, calling the case a "matter for the police."

The accusation came to light after an anonymous letter was sent to Morrison's office and to three female lawmakers last week.

The written communication contained a statement from a complainant that detailed her allegation of a rape she said took place in 1988 in the state of New South Wales.

The unnamed woman reported the allegation to police in June of last year, shortly before taking her own life.

Morrison: Allegation alone not grounds to act

Morrison said he gave the letter to police and discussed the issue with the federal police commissioner. Morrison said he had no plans to take any further action until police reported back.

"We can't have a situation where the mere making of an allegation and that being publicized through the media is grounds for ... governments to stand people down simply on the basis of that," Morrison said.

The Ministerial Code of Conduct states a "minister should stand aside if that minister becomes the subject of an official investigation of alleged illegal or improper conduct."

jsi/msh (AFP, AP, Reuters)