A child has died and two adults are seriously injured after a single-vehicle crash on the Hume Highway in the state’s south this morning.

The crash happened about 9.15am (Sunday 7 June 2015), 10km south of Tarcutta, when a northbound Volkswagon sedan left the highway and hit a tree.

A woman and child travelling in the back seat were trapped for an hour before being released.

The four-year-old boy died at the scene.

The woman and the 39-year-old man, who was driving, were airlifted to Canberra Hospital by the Snowy Hydro South Care Helicopter.

Both adults are reported to be in a serious condition.

The Hume Highway’s northbound lanes were closed for the helicopter to land. It will remain closed with diversions in place while police continue their investigations.

All southbound lanes are open.