Police and emergency services responded to a serious single-vehicle crash on the Tasman Highway, north of Triabunna shortly before 10am today.

A white dual-cab ute had left the roadway and crashed into a tree while travelling south, near Hermitage Road.

The driver and one passenger were treated for serious injuries at the scene by paramedics before being airlifted to the Royal Hobart Hospital by the Westpac Rescue Helicopter.

Three other passengers were treated for non-serious injuries at the scene.

The Tasman Highway was closed until shortly before 4pm, to allow emergency services to respond and conduct scene examinations.

Police would like to thank motorists for their patience and understanding.

The highway is now open.