Car veers off bridge after NSW crash

A woman has serious injuries after her car was hit from behind, sending it over a bridge on NSW's Central Coast.

The woman, believed to be aged in her 50s, was trapped for about 30 minutes near Stockton Creek Bridge on the M1 Pacific Motorway at Morisset on Monday morning.

Police allege a 20-year-old P-plate driver hit the woman's car, sending it over the bridge and into a creek.

She was freed by paramedics and airlifted to John Hunter Hospital with serious head, chest, leg and arm injuries.

The other driver escaped uninjured, but he has been arrested and will undergo mandatory blood and urine tests.

Meanwhile, in NSW's central west, a Canadian teenager died when her car struck a power pole about 10 kilometres south of Canowindra on Sunday night.