Nats boss asked for Joyce claim in writing

But he insists he is not behind the leak of the identity of Catherine Marriott, a former West Australian Rural Woman of the Year.

"The confidentially that we were imposed on by her solicitor and mine we have kept," Mr Anthony told Sky News on Monday.

He said the allegation was put to him by the leader, deputy leader and a former leader of the Western Australian Nationals on February 19.

"I said to them, well if this a substantial complaint then it needs to be put in writing," he said.

The president said he had many calls from other MPs in the last week telling him about the issue.

"Many people contacted me well before this came, who knew this individual, who knew the allegations," he said.

"It wasn't as if this was a secret. It was well known by the WA National Party."

Victorian MP Andrew Broad on Sunday night suggested the Liberal Party leaked the details of Ms Marriott.

"I know of a Liberal MP who had access to that letter when we had not seen it," he said.

When asked if he was blaming the Liberals for the leak, Mr Broad said: "I'm just saying that I was aware that a Liberal MP has access to it."

He declined to name the MP in question.

Cabinet minister Mathias Cormann, who was acting prime minister last week, said he was not aware how the allegations became public.

"I certainly was not aware of the complaint and I don't believe that anybody else in the Liberal Party was aware of the specifics of the complaint that was made," Senator Cormann told ABC radio.

Ms Marriott broke her silence on Saturday and said she never intended the explosive allegations - denied by Mr Joyce - to go public.

She had asked the party to undertake a formal and confidential investigation to ensure there was accountability.

Mr Joyce called the allegations "spurious and defamatory" when he flagged his resignation as party leader and deputy prime minister on Friday and called for them to be referred to police.

Australian Associated Press