Baby killed, mum and dad hurt in car crash

A two-month-old girl is dead, her parents are in a critical condition and two other relatives have been hurt in a car crash in northern NSW.

The accident caps a terrible 24 hours on the state's roads, with two other motorists dying on the south and central coasts.

The baby was in a Holden Commodore that collided with an oncoming Ford sedan on Uralla Road at Armidale on Wednesday morning.

She suffered serious injuries and died at the scene.

The baby's 20-year-old mother was flown to Newcastle's John Hunter hospital in a critical condition with head injuries and fractured bones.

The girl's 22-year-old father was flown to Royal North Shore Hospital in a critical condition with a fractured skull and shoulder.

Two other members of the same family - a 47-year-old woman believed to be the baby's grandmother - and a 24-year-old man, were in the Holden.

They both suffered minor injuries and were treated at Armidale Hospital.

The female Ford driver was taken to Armidale Hospital for assessment and mandatory blood and urine testing while her son, who was travelling with her, was unhurt.

An investigation into the crash, which happened near the intersection of Moore Park Road, is underway.

Meanwhile, a 60-year-old Sydney man died on Wednesday morning after his van crashed into a power pole on the Princes Highway near Milton, on the state's south coast.

In Gosford, a 35-year-old man died on Tuesday evening after his motorcycle allegedly hit the kerb of a roundabout and collided with a metal pole.

The Ambulance Service of NSW urged drivers to take extra caution on the south coast, amid heavy rain.