Wellington, March 20 NZPA - Blenheim police will conduct a post mortem on a 51-year-old local woman who was killed when a suspected drunk driver collided with her car after fleeing a police checkpoint last night.

Detective Richard Rolton told NZPA a 20-year-old woman had been stopped at an alcohol checkpoint on Alfred Street about 9.45pm.

A passive breath test indicated she had been drinking and the woman was asked to pull to the side of the road to take a breath screening test.

"Before being able to carry out (the test), the driver accelerated away from the checkpoint," Mr Rolton said.

Officers found the car about 400 metres down the road at a roundabout on Hutcheson and Nelson Streets, where it had collided into another vehicle.

They went to help the driver of the second vehicle but she had suffered fatal injuries.

The 20-year-old was taken to Wairau Hospital with minor injuries and has since been discharged.

A blood sample has been taken from the woman and will be examined to establish if she was affected by alcohol.

Police had not been pursuing the 20-year-old's vehicle at the time of the crash.

Police have now completed a scene examination and are appealing to any witnesses to the crash to contact them.