Two fatalities as double demerits kick in

Two people have died in separate crashes on NSW roads in the past 24 hours as police urge drivers to take care over the Australia Day long weekend.

A man aged in his 50s died on Thursday night on the Hume Highway at Douglas Park, on the outskirts of Sydney, when his car left road and hit a tree.

Earlier a 55-year-old motorcyclist from Sydney died when he left the road and hit a tree on Sir Bertram Stevens Drive at the Royal National Park at Garie Beach.

It's been a horror week with road fatalities, including the death of a seven-year-old boy on Wednesday, which brought the toll to 15 in the past seven days.

Double demerit penalties start on Friday and will last until Monday as NSW authorities look to limit road deaths over the long weekend.