Two Toronto cyclists are selling rolls of stickers meant to shame drivers who park their vehicles in bike lanes.

The anonymous cyclists are selling 3-inch neon green stickers that say "I Parked in a Bike Lane," encouraging vigilante cyclists to slap the stickers on offending vehicles.

Those involved are then snapping photos and posting them to social media using the hashtag #IParkedInABikeLane.

One of the cyclists behind the campaign told CTVNews.ca that the idea for the stickers came from a conversation about the challenges of riding a bike in Toronto.

"Drivers blatantly ignore bike lanes and cyclists in general," the cyclist said in an email.

"We got a roll of stickers for ourselves and to give to our friends, we didn't expect it to blow up like this."

Due to the stickers' popularity among friends, the cyclists took to the Internet to sell the product, and said they sold out of the first 1,000 printed in one week.

The stickers are available for purchase online and they've been sold across Canada and the U.S., the U.K., Sweden, Germany, Australia, Singapore and Brazil, among other countries.

A roll of 20 stickers costs $5.

The cyclists say they are not associated with any businesses or organizations, and warn those who buy the stickers that they may be “confronted with aggression or legal implications from drivers.”

In a message on the cyclists' Tumblr, the pair wrote: "If you've reached this page because you're angry someone stickered your car, the solution is really simple - don't park in bike lanes."

They say the intention isn't to cause damage or vandalize cars, it's to get drivers to change their actions in the future.