Police have launched an investigation into arguably Australian sport’s most bizarre Mad Monday story – claims an AFL player set fire to a dwarf.

Dwarf entertainer Arthur Serevetas says his colleague Blake Johnston, who performs under the moniker Mr Big, had his clothing set alight by a St Kilda player running rampant with a stove gas lighter.

The duo, who charge $500 per two hours according to their website, were hired to perform for Saints players the day after their season-ending win over Fremantle on Saturday as part of post-season celebrations.

“Part of his shirt and pants caught on fire,” Serevetas told the Nine Network’s Footy Classified on Monday night.

“After that someone put it out and he got ticked off and we basically left.”

Police confirmed to AAP a complaint had been lodged over the alleged incident, said to have happened at a South Melbourne hotel.

South Melbourne’s crime investigation unit is probing the claims.

“I know detectives are looking at it,” a Victoria Police spokesman said on Tuesday.

St Kilda confirmed it was investigating reports involving a player at a post-season celebration on Monday.

“The club anticipates being in a position to make a further statement later this afternoon,” the Saints said in a statement on Tuesday.

St Kilda has a long, recent history of off-field controversy.

If true, the dwarf-burning stunt would join a strange catalogue of incidents in which Australian footy players have let off steam with regrettable results.

Ex-Canberra NRL player Joel Monaghan simulated a sex act with a dog in Mad Monday celebrations post the 2010 season – sparking global shame as a picture of the incident went viral.

AFL club’s North Melbourne’s tasteless 2009 video of a condom-clad rubber chicken performing sex acts – an internal prank which found its way to YouTube – was decried as offensive to women.

The dwarf incident even forced AFL chief executive Andrew Demetriou into an apology after he laughed on television when confronted with the claims.

He said he initially thought the bizarre allegations were made up by a Seven Network producer when told about them.

“I was actually giggling in the beginning because I’d been told by the producer during the break before we went onto the next segment and I thought they were having me on,” Demetriou told 3AW on Tuesday.

“I thought it was a joke.

“When this was brought up, I just thought it was incredulous to think that this could possibly be.”

Demetriou said he didn’t believe it was genuine until the story, which had been published online, was read to him.

“After I found out that it was true, it’s just reprehensible.

“I was flabbergasted, because in the scheme of all the things that we’ve been (through this season), that would’ve been one thing I could have never predicted that we would deal with.

“It (the initial reaction) wasn’t meant to be offensive and I apologise to anyone who is offended.”

Demetriou planned to contact Johnston on Tuesday to see how he was and to apologise for his initial reaction.

“I wasn’t directing my laughter at him, I just couldn’t believe the situation could occur.

“I don’t understand, unless someone can explain, what’s the purpose of having lighters? I don’t get that.

“We spend our whole lives telling children not to play with matches … “

Demetriou said the AFL was in the process of gathering all the facts from St Kilda.