Traffic on the Hume Freeway was slowed as emergency services worked to free a trapped driver, after a multi-truck collision between Wallan and Wandong this morning.
Paramedics were called to the scene about 7am.
An air ambulance was on site as emergency workers have freed the driver, a man in his 20s.
The trucks were travelling northbound on the freeway when it is believed the smaller truck crashed into the rear of the larger one.
Paramedics treated the man for serious injuries to his lower body, and he was airlifted to the Alfred Hospital.
The exact circumstances of the collision are still to be determined, as emergency officials work to clear the scene.
Drivers were urged to use the Northern Highway and Wandong Road as an alternative route.