A 22-year-old man has been arrested after a police officer was injured when she was dragged under a stolen patrol car in Christchurch last night.

The incident happened at an alcohol checkpoint on Buchanans Rd near Hornby about 11.30pm, after a man had his licence suspended and keys confiscated after failing a breath alcohol test, Canterbury road policing manager Inspector Al Stewart said.

"After being summonsed to appear at court, he has been released and has left the area. A short time later he has returned to the checkpoint and accessed an unmarked police vehicle, which he has attempted to drive away," Mr Stewart said.

"A senior female constable has tried to stop this person and has been dragged along the road for approximately 10m, suffering a laceration to her head and tissue damage to her leg and ankle."

The man abandoned the car a short distance away, where it was recovered undamaged, he said.

" The driver was arrested this morning at his home address in Papanui and will face charges relating to assault, unlawfully taking a car, and various driving charges due to the status of his licence and level of intoxication."

Mr Stewart said the practices around the security of patrol cars at alcohol checkpoints would be reviewed, and last night's incident would form part of that process.

An eyewitness told Radio New Zealand she saw the man flee after abandoning the car in a hotel carpark near the Riccarton Racecourse.

"We heard the screeching of wheels and a car came around the corner, just about lost it on the corner, and then came flying in through the carpark of the hotel," she said "He came to a grinding halt just before the fence and the guy jumped out and took off over the fence."