Rider critical after northern Tas crash

A motorcyclist is undergoing surgery after colliding head-on with a car in northern Tasmania.

The accident happened in Rocherlea, near Launceston, shortly before noon on Sunday, a Tasmania Police spokesman said.

It's believed the rider lost control and crossed double lines.

The 51-year-old rider was taken to the Launceston General Hospital, in a critical condition, for surgery.