The cars, a Mitsubishi Colt and a silver Mazda 626, were travelling in opposite directions when they collided about four kilometres south of the Macarthur Drive intersection shortly before 2pm.

The driver of the Mitsubishi, a woman in her 60s, and a male passenger of a similar age both died at the scene.

The 18-year-old driver and only occupant of the Mazda was airlifted to Liverpool Hospital in a serious condition. His injuries were not believed to be life-threatening.

Camden police commander Superintendent Ward Hansen said police were still working to confirm the details of what happened and identify the victims.

‘‘We believe [the deceased] are in their 60s, but that’s all to be confirmed," he said.

He said it was too early to say where the victims were from, as next of kin were still to be notified.

Supt Hansen could not confirm whether it was raining at the time of the crash, but said all motorists should adhere to the road and weather conditions when driving.

‘‘[The crash] is the subject of an investigation and we’ll be preparing a report for the coroner,’’ he said.

‘‘Metropolitan Crash Investigation Unit is conducting investigations, supported by Forensic Services Group and assisted by Camden Local Area Command.’’

A driver who pulled up at the scene not long after the crash said about 10 people stopped and tried to help.

He said the 18-year-old was distressed and frightened.

‘‘We covered him with blankets, he was in shock and shaking,’’ the witness said.

He said it took under 10 minutes for emergency services to arrive.

Picton Road was closed in both directions between Macarthur Drive and the M1 for several hours while emergency services worked to clear the scene.

The accident was the first fatality along the stretch of road since works improving its safety, including the installation of concrete medians and widening parts of the road, were finished last year.

In August 2011, a 28-year-old Mangerton man died on Picton Road when his ute crossed to the wrong side of the road about two kilometres east of Cordeaux Dam Road and collided head-on with a fully loaded car carrier.

In 2005, a Balgownie man died when his ute collided with a truck and in 2006 a Grafton truck driver died in the same place when his semi-trailer crashed into trees near the Cordeaux Dam Road turn-off.