A man is in a critical condition in a Newcastle hospital after he was hit by a car his partner was driving and pinned underneath before she drove off.

Police said that at about 8.15pm (AEDT) on Saturday a 38-year-old woman was in her car in West Wallsend on the NSW central coast when her 43-year-old partner came to the window to talk to her.

She started to drive away, completing a u-turn, as the man walked alongside the car before stopping in front of it.

Police said the car then hit the man who was trapped underneath it for a short time, before his partner drove away.

The man was taken by ambulance to John Hunter Hospital with serious injuries and remains in a critical condition.

At about 10.20pm the woman went to Toronto Police Station and after being taken to hospital for mandatory testing she was released pending results of the tests and further investigations by detectives.

Police are urging anyone with information or who may have witnessed the incident to contact Lake Macquarie police or ring Crime Stoppers on 1800 333 000.