Two people were seriously injured and one person was seriously injured when a car flew during road works, hit a bridge and rolled into the ditch.

Emergency services were called to the scene on a closed section of State Highway 16 in Huapai at 12.45am.

A St John spokesman said two people were in a critical condition and another was seriously injured.

The spokesman said three ambulances, an emergency response unit, an operations manager and an Auckland Westpac Rescue helicopter were sent to the scene.