A Cooranbong father, 35, and a Hamilton man, 56, are believed to have died instantly when their cars collided head-on at about 11.15pm on Friday.

The deaths occurred about 275 metres south of Ballin Close near where the road crosses over the M1 Pacific Motorway.

The deaths follow 10 other fatalities, and at least six other serious accidents, on the rural road since 2000.

Police are preparing a report for the Coroner.