Manitoba Public Insurance has a warning for motorists following a spate of vehicle fires: don't plug in your vehicle if you're parking it in a garage.

The public auto insurer says in the last three weeks, nearly a dozen vehicle fires have started due to faulty or corroded extension cords. A couple of garages have caught fire as well.

"It's a concern. We have had them, so we're trying to pass that on to the public," MPI fire investigator George Murray told reporters on Friday.

Motorist Errol Schultz said it's common sense to leave vehicles unplugged in the garage.

"It doesn't make any sense — I mean, the car’s not going to freeze in there, so the block will stay warm enough that when you start your car, it’s fine," he said.

In addition to warning people that it's not necessary to plug in their vehicles in garages, MPI also wants to emphasize how important it is for drivers to inspect their extension cords.

Every year, about 1,000 vehicles are damaged by fire in the province, with about 50 of those fires resulting from frayed extension cords or worn-out block heater plugs, according to Murray.

Murray showed reporters a car that caught fire in November, when a frayed cord welded itself onto the front bumper.

"When you see a cord, and he's got all these cuts, and he's spliced it and he's taped it — that’s not a good thing," said Murray.

MPI officials recommend that motorists cover their block heater plug-in with its protective cover, unplug their block heaters by using the hard, rubber end, and have it inspected each fall by a mechanic.

Officials said drivers should never allow their cords to dangle or drive over them.

"A guy driving down Plessis with an eight-foot cord dragging and flipping and smacking all over — now that guy goes home and plugs it in, and he doesn't know what's occurred there," said Murray. "There could be all kinds of damage."

MPI estimates that vehicle fires caused by faulty extension cords cost upwards of $4 million to $5 million a year.

Winnipeg fire officials have also been warning people against plugging in their vehicles inside garages or keeping their block heaters running.

Officials have said garages usually provide enough shelter to ensure a vehicle will start even in the coldest temperatures.