The event on Tuesday earned Gatto's associates and Swan several thousand dollars and was attended by several other members of Gatto's ''Carlton Crew'', including fellow convicted criminal Angelo "Fat Ange" Venditti.

Gatto and Venditti both beat separate murder charges during the underworld war and Venditti has previously sparked controversy over his relationship with troubled former AFL star Ben Cousins.

Also at Coburg pizza restaurant Gatto Nero - majority owned by Gatto's brother John - were several other underworld-linked figures and members of the public.

Collingwood chief executive Gary Pert on Wednesday sought to play down Swan's appearance at the event, despite the AFL recently warning clubs and players to stay away from organised criminals, given the threat they pose to the integrity of the game.

Pert said the Brownlow medallist had ''assured us he didn't know anyone there'' and the event was a typical ''commercial exercise'' organised through his manager Liam Pickering. But Pickering told Fairfax Media on Wednesday night that he had no knowledge of the function and was told by Swan it was organised by a personal friend of the player.

Fairfax Media can reveal that one of Swan's closest friends, former VFL player Aaron Ramsay, was at the event and was well aware of its association with Gatto. Ramsay and Swan were ordered to perform community work after they pleaded guilty to affray over a drunken fracas at Federation Square in December 2003.

Ramsay works for his family's construction company, with several members of the Gatto family, including John and two of Gatto's relatives who own the photo-booth business that was used at the Swan dinner.

Mick Gatto has a close association with the construction firm owned by the Ramsay family.

"It is utter crap that Swan would not have known who was going to be there. His best mate [Ramsay] works with Gatto's relatives," a source at the event said.

Around 50 people paid between $60 to $200 to see Swan speak and to bid for signed Collingwood jumpers and other sporting memorabilia.

Gatto Nero spent several days promoting the event - as did John and Mick Gatto - and designed a flyer inviting people to "an evening with Dane Swan".

Pert said the club had been unaware of Swan's appearance at Gatto Nero until contacted by Fairfax Media but immediately sought details from Swan.

Swan told Collingwood officials he had no meaningful links with the Gatto family, claiming he had met Mick Gatto once previously and did not known any other guests at the function. Swan told the club that Pickering had organised his appearance.

Swan also said he had stayed at the function for 90 minutes, delivered his speech and then departed.

However, a photographer who took pictures outside the event, and guests who contacted The Age about it and recorded some phone footage inside Gatto Nero, said Swan was at the event for at least three hours and mixed with several underworld identities, including Mick Gatto.

Photos from inside the event show Swan posing for photos with Mick Gatto, who has been banned by the Victoria Police from racecourses and casinos and has been repeatedly investigated by the Purana organised crime taskforce.

The AFL's new senior integrity investigator, Gerry Ryan, is a former detective superintendent of the Purana taskforce and his detectives previously investigated Mick Gatto for money laundering, tax evasion, drug trafficking and murder. Gatto has not had a serious criminal charge proven against him for over a decade. He was acquitted of murdering hitman Andrew Veniamin in 2005.

He is currently being pursued for tax evasion by the Tax Office and is understood to deal largely in cash and has moved many of his assets into the names of his associates.

On Thursday morning, Mick Gatto told ABC Radio's Jon Faine that the media are to blame for making an issue of Swan's appearance at the restaurant.

"There's nothing in it," he said. "Dane Swan's a real champion of a man. He came over and briefly spoke to me, I asked him for a photo and he said yes.

"It's never a problem until the media makes it a problem ... Nothing to do with me. I went there, I bought a table, I filled a table with elderly friends of mine, not underworld figures. We had a nice night out, we listened to Swannie talking about footy or whatever.

"What's he [Swan] done wrong? He's there doing a fund-raiser or whatever he's doing," Gatto said.

"Unfortunately I am tainted and it's going to be that way for the rest of my life, that's the way it is and there's not much I can do about it.

"I walk with my head held high. I believe I've paid my dues. I'll continue to walk with my head held high.

Asked about his tax problems, Gatto said: "This is their [the Tax Office's] last hurrah. I owe them nothing, but they've targeted me because it's their last hurrah and they say 'wipe him out.'"

New AFL chief executive Gillon McLachlan, who discussed the Gatto event with Pert on Wednesday, said he would not comment until he had gathered full details of the function.

But Pert said he did not have an issue with Swan speaking at the Gatto function.

This is despite the AFL over the past 18 months having received repeated warnings from the Australian Crime Commission that organised crime figures were working to infiltrate Australian sport and, more specifically, the AFL.

Pert said: ''We've just got to trust our player managers putting our players out there.

''It's one of those situations where the players have to trust people around them."

Collingwood chiefs Pert and president Eddie McGuire confronted Swan and Pickering towards the end of 2012 over serious concerns regarding the star player's off-field behaviour. The intervention took place shortly after Pert had officially alerted the AFL and all 17 other club chiefs to AFL footballers' illicit drug use during the off-season. He described the situation at the time as ''volcanic''.

At the start of the 2014 season, outgoing chief executive Andrew Demetriou slammed Richmond player Jake King's connection with bikie boss Toby Mitchell, disputing the suggestion that AFL players could mix with whomever they chose.

Pert told Fairfax Media that the Swan incident was ''a very different scenario . . . this was simply a commercial exercise for him [Swan]. We certainly would have an issue with our players if a situation like the ones we've seen recently in the AFL but this is nothing like that. He has assured us he didn't know anyone there, he spent an hour-and-a-half there, he spoke, he ate his dinner and he left.''

Follow Nick McKenzie on Twitter @ageinvestigates