Australian Football League side St Kilda were Tuesday investigating claims that one of its players set a dwarf performer on fire at the club's end-of-season celebrations.

Blake Johnston and his colleague Arthur Serevetas were reportedly booked by the Saints to entertain players at their so-called "Mad Monday" event this week, but it allegedly got out of hand.

Channel Nine said a group of players began using a cigarette lighter to set fire to each other's clothes as a prank, before one, who has not been named, is said to have turned his attention to Johnston, who goes under the moniker Mr Big.

"A player went behind my friend with one of those gas lighters that you light up a stove and basically lit him up," Serevetas told the broadcaster's Footy Classified.

"Part of his shirt and pants caught on fire. After that someone put it out and he got ticked off and we basically left.

"That was the end of our gig basically."

The performer was quickly helped by other players and suffered only minor injuries, the reports said.

Serevetas said he considered the St Kilda player's actions as criminal and had advised his colleague to take action.

A club spokesman told "The club is investigating and is unable to add anything further at this time."

AFL chief executive Andrew Demetriou came under fire for giggling when he was asked about the incident on Channel Seven.

He later apologised, saying he thought it was a joke.

"I was actually giggling at the beginning... because I thought they were having me on. I thought it was a joke," he said.

Aussie Rules has endured a tough season, with Essendon coach James Hird banned for 12 months and the side hit with the biggest fine in the sport's history -- Aus$2.0 million (US$1.8 million) -- over a drug supplements scandal.

Watch a report on the incident, posted on YouTube by user 'BreakingNews,' below.