A 37-year-old Cardiff South woman is in a critical condition after a Harley Davidson motorcycle crashed at Aberglasslyn.
The incident happened in Denton Park Drive shortly after 9.30pm on Saturday.
The male rider, also 37, suffered fractures. The Rutherford man is in a stable condition.
Police alleged the Harley hit a concrete median strip, then a parked car.
Two Westpac rescue helicopters flew to the scene, but NSW Ambulance paramedics treated the injured pair before taking them to John Hunter Hospital by road.
Port Stephens Hunter police said the female pillion passenger was in a critical condition and undergoing surgery.
A NSW Ambulance statement said the woman had "possible head and spinal injuries" and the man "possible head, chest and wrist injuries".
The Hunter Crash Investigation Unit is investigating the incident.
Meanwhile, a single-storey house was destroyed by fire in Vindin Street, Rutherford on Saturday night.
Firefighters were called to the scene at about 9.50pm.
A number of pet cats died in the fire, a Fire and Rescue NSW spokesperson said.
A NSW Ambulance spokesperson said three people were treated for smoke inhalation, including a man who was taken to John Hunter Hospital.