SYDNEY (Reuters) - A red-faced Australian nudist who tried to set fire to what he thought was a deadly funnel web spider's nest ended up with badly burned buttocks, emergency officials said Monday.

The 56-year-old man was at a nudist colony near Bowral, about 60 miles southwest of Sydney, Sunday when he spotted what he believed to be a funnel web spider hole.

Ambulance workers, including a helicopter crew, were called to the scene after the man poured petrol down the hole and then lit a match in an attempt to kill the offending arachnid.

"The exploding gasoline fumes left the man with burns to 18 percent of his body, on the upper leg and buttocks," the NRMA Careflight helicopter rescue service said in a statement.

It said the man's lack of clothing probably contributed to the extent of his burns.

"The fate of the bunkered spider was unknown, although other guests at the resort thought it was probably a harmless trapdoor spider and not a deadly funnel web," the statement said.

NRMA Careflight said it was called to a property in the same area in January when another man kicked a spider that was crawling up the wall of a friend's cabin. The man broke his leg in two places, it said.