Liberal Party official Barrie Macmillan, who was caught on tape conspiring to funnel donations from alleged Mafia boss Tony Madafferi to Victorian Opposition Leader Matthew Guy's campaign, has resigned from his party positions.

Mr Guy is under increasing pressure after it was revealed he ate at a lobster restaurant with a group including Mr Madafferi earlier this year.

Liberal Party president Michael Kroger (left) with Barrie Macmillan. ( Facebook )

But on early Wednesday, Mr Guy said he would discuss Mr Macmillan's future with the party's state president, Michael Kroger.

"I think he [Mr Macmillan] will move on and I think that will be the right thing to do," Mr Guy said.

Mr Macmillan had been the secretary of the party's Dunkley Federal Electorate Conference and the vice chair of the Hastings Federal Electorate Conference.

According to his LinkedIn profile, has worked for the party for almost five years.

In recorded phone conversations obtained by Fairfax Media and Four Corners, Mr Macmillan said a promise of donations was made after the lobster dinner.

He was also recorded saying he was trying to organise a second dinner with Mr Guy, Mr Madafferi, Mr Madafferi's cousin Frank Lamattina and two other Madafferi relatives.

"Frank [Lamattina] rang me and said, 'Look, four of us guys would like to have a dinner with Matthew, and we want to push some dollars his way', and I said, 'Well, look, we have to be extremely careful there'," Mr Macmillan said in the recording.

"Frank's no fool. He knows that there's the AEC [Australian Electoral Commission] follow up and all these things.

"They want to meet again now, and I've had to speak to Kroges [Liberal president Michael Kroger] about it," Mr Macmillan said, indicating the donations would be made later this year.

Matthew Guy has been under pressure since details of the dinner emerged on Tuesday. ( AAP: Joe Castro )

State Liberal Party director Simon Frost had a short meeting at Mr Macmillan's home on the Mornington Peninsula this afternoon.

He issued a statement shortly after, saying he had accepted Mr Macmillan's resignation.

"I have today accepted Mr Barrie Macmillan's resignation as a local electorate conference office bearer of the Victorian Liberal Party. I will not be making any further comment on this matter," he said.

Earlier, outside Mr Macmillan's home, Mr Frost said the party would continue to back Mr Guy as leader.

"The party, from the president to myself down, and all the senior office bearers are 110 per cent behind Matthew Guy," he said.

Mr Guy, who has referred the matter to Victoria's anti-corruption watchdog, said none of the men at the dinner had made donations.

The Lobster Cave in Melbourne's south-east, where Victorian Opposition Leader Matthew Guy attended a dinner with Tony Madafferi. ( Four Corners )

"I don't know anything about those phone conversations, everything I know about this instance I made very clear and very public yesterday," he said.

"You'll have to ask the people involved in those conversations because, as I said, no donations have been forthcoming to the party, and if one individual has sought to solicit something or get something, well that's up to him to answer."

Prime Minister Malcolm Turnbull told Parliament this afternoon that federal authorities would examine the issues raised by the recordings.

Mr Turnbull was asked by Shadow Attorney-General Mark Dreyfuss if the Government had asked the Australian Federal Police to investigate.

"I can assure the honourable member that those [media] reports will be carefully examined by federal authorities," Mr Turnbull replied.