An Australian man who set his own pants on fire instead of a building has given new meaning to the word arsonist.

A would-be arsonist was on the receiving end of instant karma during a Christmas Day attack that embarrassingly backfired.

Victoria Police released CCTV of the incident at a fast-food store which shows a pair of suspected arsonists pouring flammable liquid on the front of a Melbourne burger joint around 2.40am on Christmas Day.

But as the pair lit the fire, the trousers of one of the men went up in flames.

The surveillance footage captured the moment which shows the culprit panicked and running down the street with his pants on fire.

The scorched arsonist is seen frantically trying to douse the flames as his accomplice watches on making no effort to help him.

Desperate to avoid toasting his buns, the flaming arsonist pulled his pants and underwear off before running down the street with his bare butt showing for the camera.

Police said the two men on camera ran to their getaway vehicle, a Tarago van being driven by a third offender.

Police hope releasing the footage will help them find the alleged offenders.

A would-be arsonist stripped bare after setting his pants and underwear on fire in a Christmas Day attack that backfired.

“It is believed two people arrived at the premises in white Toyota Tarago before pouring a flammable liquid over the front of the store,” Victoria Police said in a statement.

“After setting the liquid alight, one of the offenders also succeeded in setting their pants on fire, forcing them to strip their burning garments as they fled.

“The Tarago, which is believed to have been driven by a third offender, was last seen headed east on Doncaster Rd.”

Police said they found singed pants, underwear and shoes at the scene.

Sprinkers were activated inside the store but no substantial damage was done to the burger joint.

- NZ Herald