The Federal Government has been rocked by a historial rape allegation against a standing member of the federal cabinet. 

Prime Minister Scott Morrison is among several high-profile politicians to have been sent an anonymous letter about a 33-year-old allegation of rape against a Cabinet ministers.

The woman made the allegation to the NSW police last year, but took her own life before making a formal statement.

The unnamed minister has reportedly denied the allegations. The letter has been referred to the Australian Federal Police.

The PM is facing calls for the minister to be stood down while an investigation. 

Several members of cabinet have called for the issue to remain a police matter, not a political one, but it is extremely unlikely authorities will be able to make a case now that the alleged victim is dead.

Mr Morrison has not commented on the claims in the days since they were aired.

Marque Lawyers partner Michael Bradley - who acted for the woman when she made her complaint to police - says the minister at the centre of the claims must step aside. 

“I think he will have to stand aside, at the moment at least, because he’s been accused of such a grave crime,” Mr Bradley has told reporters.

“It’s untenable for him not to, I would think. It’s not really a legal question, it’s a question of propriety.

“It goes to his ability to do his job. It’s necessary that his integrity is not under serious question.

“And it’s about the integrity of the entire government – whether it can carry on with a cloud this huge hanging over it.”

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