POLICE are investigating a fatal collision south of Wallan on Saturday night.

Police say two cars collided head-on on the Northern Highway, about 200 metres north of the Hume Freeway, at about 11.30pm.

A male driver died at the scene, while his female passenger was airlifted to hospital with serious injuries.

The driver of the second vehicle was transported by road ambulance to hospital with non-life-threatening injuries.

A spokesperson from Wallan Police Station told the Review the investigation was ongoing, and police were still in the process of notifying family members, some of who appeared to be overseas.

The spokesperson said the incident appeared to be the result of driver error.  

The Northern Highway was closed in both directions at Wallan folllowing the crash, with traffic diversions in place while police investigated the scene on Sunday.

Police urge anyone who witnessed the incident or has dashcam footage to contact Crime Stoppers on 1800 333 000 or submit a confidential report at www.crimestoppersvic.com.au.