Julia Gillard’s former boyfriend has claimed he was offered $200,000 to make a false statement about who paid for renovations to the former PM’s house.

The one-time boyfriend of Julia Gillard will appear before the royal commission into union corruption to answer questions over his claim he was offered money to give evidence against the former prime minister.

Bruce Wilson will be questioned on Thursday about his claim he was offered $200,000 to say that he paid for renovations to Ms Gillard’s Melbourne house in 1994.

The claim is made in a statement by Mr Wilson to the royal commission into union corruption, parts of which were read on air by ABC Melbourne radio presenter Jon Faine on Tuesday.

Mr Faine said he was reading the statement but could not verify its accuracy and made no claim as to its truthfulness.

In the statement, which has not been made public, Mr Wilson claims he was contacted by lawyer Harry Nowicki in 2012 and subsequently met Mr Nowicki and another man, “Z”, in Nelson Bay on the NSW mid-north coast.

Mr Wilson claims Z told him “there’s money” and that “there are a number of benefactors prepared to support you”.

The statement goes on to claim that Mr Nowicki mentioned a sum of $200,000 if Mr Wilson would make a statement about Ms Gillard.

“We just needed a statement to start. Say something like `I paid for renovations to Gillard’s house but I can’t recall where the money came from’,” Mr Wilson’s statement says.

Mr Wilson says he refused and told the men the allegations were untrue.

Mr Nowicki has denied Mr Wilson’s claims, telling reporters on Tuesday that he believed Mr Wilson had fabricated evidence and had defamed him.

“I’ve had four meetings with Bruce and every meeting I’ve had with him I’ve said ‘Bruce, this is a significant story and your role is to tell the truth’,” Mr Nowicki said.

Mr Nowicki, a former industrial lawyer, is writing a book about the Australian Workers’ Union (AWU), which is embroiled in the so-called slush fund affair that dogged Ms Gillard throughout her prime ministership.

The commission has heard evidence that Ms Gillard, who was a lawyer at Slater and Gordon in the 1990s, helped to set up a fund that was used by her then-boyfriend, Mr Wilson, to receive payments when he was an official with the AWU.

Ms Gillard has consistently denied any wrongdoing or knowledge of any impropriety.

Mr Wilson will appear before the royal commission in Sydney on Thursday.

Mr Nowicki later told ABC TV he believed Mr Wilson made a “colossal mistake” in giving a “totally fabricated” statement to the commission.

He denied offering Mr Wilson any cash inducements, but admitted paying for several flights to meet with him for information about the union fund.

Asked about his motivation, Mr Nowicki said it was important for the “facts” to come out about Ms Gillard’s rise to power.

“How is it possible that someone involved … in questionable behaviour becomes prime minister?” he said.

“That’s a political story, that’s not my story.”

Mr Nowicki also admitted to paying former AWU official Ralph Blewitt $5000 in travel costs and writing his witness statements to Victoria Police.