Senior Morrison government ministers have stressed a cabinet colleague accused of a horrific historical rape is entitled to the presumption of innocence.

Greens senator Sarah Hanson-Young, Labor’s Penny Wong and Prime Minister Scott Morrison were sent a letter detailing the complaint last week.

The incident is alleged to have occurred in 1988, when the woman was 16.

The woman went to NSW police in 2020, but the investigation was suspended when she took her own life after telling authorities she didn’t want to proceed.

• MPs admit they knew of rape allegations

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Treasurer Josh Frydenberg said the matter had been referred to the Australian Federal Police.

“We in Australia adhere to the rule of law. The rule of law means there is a presumption of innocence,” he said in Devonport on Monday.

Senator Hanson-Young said the minister must stand aside pending an independent investigation by an eminent former judge.

“It is just not right to suggest that this type of allegation could linger, hang over the heads of the entire cabinet,” she told ABC radio.

“Sitting around that table erodes the trust the integrity and belief that this government takes sexual assault seriously.”

Cabinet minister Darren Chester said the investigation needed to take its course.

“Otherwise we do lend ourselves to a dangerous path where people make outrageous allegations about others in the community and force them to stand aside from their jobs with quite vexatious claims,” he told Sky News.

He said sexual violence against women was a major problem the country needed to deal with.

Marque Lawyers managing partner Michael Bradley, who represented the woman when she took the complaint to police, questioned whether the minister could do his job with his integrity under question.

“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 told Nine newspapers.

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

Liberal frontbenchers Angus Taylor and Jane Hume also insisted the matter should be left up to police.

Labor leader Anthony Albanese said the allegation needed to be investigated appropriately and not politically managed.

Former prime minister Malcolm Turnbull received a letter from the woman in late 2019 asking for his advice.

“She described a pretty horrific rape that she said had occurred at the hands of this person, a person she said is now in the cabinet,” he said.

Two federal MPs have also admitted they knew of the claims before they became public on Friday.

Labor MP Daniel Mulino said the alleged victim, who was also his friend, had contacted him in December 2019 about wanting to “proceed with a formal complaint”.

He told the ABC he “supported her in that decision” and ensured she “was receiving appropriate support”.

The ABC has also confirmed that WA Liberal MP Celia Hammond was also sent the 31-page dossier on the allegations.

“I received a copy of the correspondence on Wednesday,” Ms Hammond told the ABC.

Liberal senator Sarah Henderson has forwarded police an email from a woman who claims she was raped by a serving Labor MP.

The AFP confirmed they received a complaint relating to an historical sexual assault but would not comment further.

Sexual assault allegations have sparked national debate about political culture after former Liberal staffer Brittany Higgins said she was raped by a colleague in Parliament House.

Four inquiries are under way, including a multiparty investigation aimed at ensuring parliament is a safe working environment.

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-with AAP