The 40-year-old man, who has not yet been formally identified, died at the scene on Kuringa Road in Spence.

Initial investigations suggest the dead man's car was travelling at 20 or 30km above the 80km/h limit when the accident occurred at about 4am this morning.

The driver of the second vehicle, an 18-year-old woman, was badly hurt in the crash.

She suffered face and head injuries, and was taken to the Canberra Hospital in a serious condition.

Her injuries are not believed to be life threatening.

A passing motorist called emergency services almost immediately after the crash occurred.

Traffic operations Superintendent Mark Colbran said while the investigation was in the early stages, marks at the scene indicated speed was a factor.

''From the markings left on the road by skid marks and marks from the tyres it appears that the male was exceeding the speed limit, and then drifted onto the wrong side of the road, and had the head-on collision with the car coming north on Kuringa Drive,'' he said.

It is unclear whether drugs or alcohol were involved, but an autopsy is expected to be conducted later this week.

Police have appealed for any witnesses to come forward.

The death was the fourth road fatality in the ACT this year.

Anyone with information should contact Crime Stoppers on 1800 333 000.