Launceston cyclist Hilary Ivery was participating in Sally's Ride on Sunday when she was struck down from behind in a bike lane by a blue four-wheel-drive, five kilometres from the finish line on George Town Road at Newnham.

The driver did not stop.

Ms Ivery had deep abrasions on her arms and legs and deep bruising that covered her right thigh.

"I heard a four-wheel-drive and he swerved into me and his mirror hit me," she said.

"I was very lucky that I didn't go under any traffic really."

Ms Ivery said the group of six cyclists had encountered the car 300 metres earlier when the driver had opened the car door into the cycling bunch.

The cyclists had alerted him as they approached to avoid impact.

Fellow rider Peter Dadson said the group believed that the driver had swerved towards Ms Ivery, although they found the act difficult to prove to police without a licence plate.

"It was clearly road rage - it was a deliberate act to stir us up," he said.

"There could have been a fatality."

Ms Ivery added:

"We're vulnerable as cyclists and can be seriously injured. Cars should drive at least one metre away from cyclists and we need that because of the wind draught from vehicles."

She thanked members of the public and emergency officers who came to her assistance.

The incident was reported to Newnham police.