A waterbomber needed to douse forest fires in British Columbia is out of action after being damaged by vandals, as the fire risk in the province continues to climb.

Port Alberni RCMP are investigating after the horizontal canvas stabilizers on the Martin Mars waterbomber were torn by at least one trespasser climbing on the aircraft. The damage is believed to have occurred on Saturday night.

The waterbomber, moored at Sproat Lake, is contracted out by the province but is owned by the Coulson Group.

Spokesperson Jim Messer said the company is offering $5,000 to anyone with information that would lead to a conviction.

"It was malicious, it wasn't just an act of goofing off, these people had intent. There's been a few boats shooed away throughout the day and we believe it was one of these boats that came back," he said.

"We will proceed with full prosecution if we can find out what happened here."

Messer says the direct cost of damage, repairs and loss of service amounts to tens of thousands of dollars.