Someone set fire to the portable toilets in Rotary Peace Park in Whitehorse early Wednesday morning, destroying six of them.

Whitehorse firefighters were called out at 1:30 a.m. It was the fifth time in a week they had to deal with a deliberately set fire.

Six toilets were destroyed and the fire had potential to be hazardous to anyone in the area, said Fire Chief Clive Sparks.

"It is certainly noxious and probably quite toxic smoke and fumes coming off it," he said.

"Our guys are well protected with their turnout gear and their breathing apparatus but certainly anyone else who happened to be nearby when the smoke was coming wouldn't be as well protected."

The fire department estimates the damage at around $30,000.

Four fires Monday night

The latest blaze comes after firefighters were called out to four separate fires within two hours Monday night.

The first two calls came in just after 6 p.m. after people spotted small brush fires near Elijah Smith Elementary School.

Shortly afterwards, someone reported several bales of straw had been set on fire in a yard in the Arkell neighbourhood.

Then neighbours called to say someone had piled up some brush on the soccer field at the Ecole Emilie-Tremblay and set that on fire. No structures were damaged in those fires.

Sparks said the fire department doesn't have any confirmation the five fires are related but he said it's a concern when fires are deliberately set. He urged residents to report any suspicious fire or smoke.

"We really appreciate it because it means we can get out to the fires while they are still small and we can keep the damage down," he said. "Certainly having the neighbours watch out in their own areas helps us all."