A kayaker has been rescued by helicopter after spending a night in near-freezing wilderness in Tasmania.

The man in his 20s was paddling with another man in the Wilmot River in the state’s north on Sunday afternoon when he became separated from his kayak and was forced to swim downstream.

The second man made it to shore late on Sunday and raised the alarm but a search before dark proved fruitless.

Tasmania Police said the man was flown from the area by rescue helicopter on Monday morning.

“He was physically uninjured but cold from a night exposed to the weather,” they said in a statement.

Temperatures in the area dropped to below one degree overnight.

Both kayakers were wearing safety equipment including life jackets and helmets, police say.

-AAP