A truck has crashed in the Southern Highlands, blocking southbound lanes of the Hume Highway.

The incident happened just after 4am near Medway Road at Mittagong.

The truck was travelling northbound when it left the road, hit the embankment and travelled onto the southbound lanes.

A Ford station wagon travelling south hit the rear of the truck.

The 56-year-old driver was taken to Liverpool Hospital with non-life-threatening injuries.

The driver of the Ford was treated at the scene for minor injuries.

All southbound lanes of the Hume Highway remain closed.

Diversions are in place via the Old Hume Highway with the recovery effort expected to take some time.