A prominent Australian political donor, furniture king Nick Scali, has been investigated by Italian prosecutors over allegations that he tried to entice a politician to accept a two million euro bribe ($2.92 million).

Mr Scali, who has close ties to the NSW Liberal Party's fundraising arm, also has longstanding links with suspected Calabrian Mafia figures in Australia. The contact includes his involvement in a heavy-duty lobbying campaign that targeted Liberal MPs and helped Melbourne Mafia figure Frank Madafferi beat a deportation order.

There is no suggestion that Mr Scali is involved in criminal activity.

A Fairfax Media and Four Corners investigation has uncovered documents from a 2008 Italian court case in which prominent Australian-Italian politician Nino Randazzo accused Mr Scali of offering him a bribe to change sides in the Italian parliament and support Italy's then president Silvio Berlusconi.

"In particular, he told me that there was a blank cheque for me that I could fill in up to two million euro," Mr Randazzo told Italian prosecutors in 2007. "He used, I remember well, the expression: 'I want you to become a millionaire.' "

Mr Randazzo was one of two Australians voted by the local Italian diaspora to seats in Italy's parliament.

The case against Mr Scali was triggered by phone intercepts obtained during a probe into Mr Berlusconi's alleged attempts to illegally influence Italian broadcaster RAI.

But the case against Mr Scali was eventually closed due to a lack of evidence, when police could not substantiate Mr Randazzo's explosive allegations.

The revelations add to doubts over the integrity of Australia's political fundraising system, with Mr Scali having been a prominent Liberal fundraiser for over a decade. He was also a business partner of corrupt Labor powerbroker Eddie Obeid, and has supported former Labor NSW MP and factional heavyweight Joe Tripodi.

The NSW ICAC last year heard Mr Scali was among about a dozen guests at a 2011 Liberal fundraising dinner who gave cheques to Liberal MP Chris Hartcher, who is accused of masterminding a political slush fund that subverted that state's donation laws.

In his first statement to prosecutors in Naples in 2007, Mr Randazzo claimed a rich Australian furniture retailer of Italian origin had "told me very explicitly that if I were to go over to the opposition, he would pay me, or he would have me paid the sum of up to two million euro".

In a later statement, Mr Randazzo named Mr Scali as the man who had allegedly approached him with the offer.

But Mr Scali told Italian authorities the allegation was "completely fanciful" and that he had never met or spoken to Mr Berlusconi.

"I contest the accusation most absolutely. It is absolutely not true what Sen. Randazzo has declared," Mr Scali said in a statement to Italian prosecutors in September 2008.

The Italian court was more inclined to believe Mr Scali's version of events in which he said his contact with Mr Randazzo was an attempt to chase up $40,000 he had loaned the politician and an another Italian MP to help with their campaigns in 2006.

To support his position, Mr Scali produced two cheques for $20,000. In contrast, the court found no evidence to substantiate Mr Randazzo's accusation.

However, the court files detail some unusual behaviour by Mr Scali, including the use of a mobile phone SIM card registered in an associate's name to arrange a meeting with Mr Randazzo.

Mr Scali said he used his associate's phone because he had left his passport in his hotel room in Italy when he acquired a local SIM card. A friend travelling with him offered to register the SIM card in his name, Mr Scali said. Mr Scali said he has since lost the SIM card.