A 25-year-old man died late on Sunday night when a Jeep carrying five males lost control and rolled at Moore Creek, near Tamworth.A 16-year-old boy from Hallsville suffered serious head injuries in the crash and was taken to hospital in a critical condition.

NSW traffic services commander Assistant Commissioner John Hartley, said alcohol was a contributing factor in a large number of accidents.

''I am appalled at the lack of responsibility shown by a number of motorists who get into a car and think they can drive after having consumed alcohol,'' he said.

NSW Police conducted more than 70,000 breath tests and charged more than 252 people over the Labour Day long weekend as part of Operation Slowdown.

By yesterday afternoon they had caught 2839 motorists speeding and 254 people not wearing seatbelts.

There were 618 crashes, 60 more than this time last year, and 166 people injured.

Assistant Commissioner Hartley said, ''We have motorists behaving like idiots, getting into cars after drinking and then falling asleep behind the wheel, crashing and injuring themselves, their passengers and other motorists.''

ACT police breath-tested 157 motorists on Friday night, but only one returned a positive reading.

Acting Superintendent Dennis Gellatly said police issued 11 traffic infringement notices and cautioned four motorists.

''Unfortunately the long weekend did not start well with the fatal collision on Friday morning, however police are pleased that the majority of drivers in the ACT have obeyed the road rules to date,'' he said.

A 27-year-old police officer was in a critical condition yesterday after being hit by a car on Oxford Street in Surry Hills in the early hours of the morning.

She was taken to hospital with serious head injuries.

A cyclist was hurt in an accident on Oxley Hill Road, Bowral, just before midday on Sunday.

Police said a utility lost control, spun across the road and collided with the rider. He sustained a large laceration to his leg and was taken to hospital.

A 34-year-old Giralang man was killed after his motorcycle hit a kangaroo on the Barton Highway in the early hours of Friday morning.

The accident brought the ACT road toll for this year to 11.