A man who flipped his car near New Plymouth this morning got out and asked to be taken to the pub rather than the hospital, police say.

Witnesses following the driver down Henwood Rd about 9.30am saw him swerving for several kilometres before taking a corner too wide.

He overcorrected, knocked over a letterbox and then hit a railway signal light fast enough to overturn his car, and narrowly missed landing on the train tracks, they said.

Nurse Louise Hannah who stopped to help, said the man, who claimed to have swerved for a dog, had some bruises and scratches and was ''very agitated and wanted to leave''.

Another witness, Rex Hendry, said the driver was quick to call someone to pick him up before the emergency services arrived.

Constable Craig O'Doherty said he understood the man had requested to be dropped off at a pub instead of being taken to hospital but police had arrested him for obstruction nearby.

Senior Sergeant Allan Whaley said the driver was a 40-year-old man from Opunake who was known to police and had subsequently been charged with failing to provide a blood sample.