A terrified tourist got out of the car before a driver was clocked at 171kmh and tried to outrun police.

Police received several complaints about the driver of a silver Subaru Legacy before catching up with him in Clarence, south of Blenheim yesterday, Marlborough highway patrol Sergeant Barrie Greenall said.

He was clocked at 171kmh in Kekerengu, about 68 kilometres south of Blenheim.

An officer signalled the driver to stop, but instead he did a U-turn and sped off in the opposite direction, Greenall said.

Police chased the car but the driver stopped a short time later.

A Canadian hitchhiker had got out of the car in Kaikoura because he was concerned about the man's driving, a passenger in the car told police.

The passenger, a woman who knew the driver, was upset, police said.

The driver, a 21-year-old Ashburton man was arrested at 4.30pm. He was charged with failing to stop and driving at a dangerous speed. His driver's licence was also suspended immediately for 28 days.

The man's driving had put all road users at risk, Greenall said.

"I'd like to thank those members of the public who alerted us to his behaviour," he said.

"Thankfully we were able to apprehend him before his road trip ended in tragedy."

The driver was breath tested. His level was 225 micrograms of alcohol per litre of breath. The legal limit is 250mcg.

The man was bailed to appear in the Blenheim District Court on March 23.