Updated December 01, 2016 11:15:43

A man has been arrested after a French tourist was allegedly stabbed to death in what police say was an unprovoked attack in the Northern Territory outback.

NT Police said a French husband and wife were at a rest stop 30 kilometres south of Aileron on the Stuart Highway in Central Australia when an unknown man approached them, stabbing the Frenchman in the neck.

Police said they were informed of the incident after the man died at the scene on Wednesday afternoon.

The couple did not know their attacker, Detective Superintendent Travis Wurst said.

"The man has allegedly then stabbed the male tourist to the neck, in an unprovoked attack," he said.

The man fled in a car, which police stopped near Ti Tree, about 60 kilometres north of Aileron, but the man fled on foot into bushland.

He was arrested in the area about 8.30am on Thursday.

A crime scene will remain in place for the rest of the day, and police said they would continue to speak with witnesses to establish the exact circumstances surrounding the French tourist's death.

His partner is being treated for shock at Alice Springs Hospital.

Police are due to hold a press conference in Darwin this morning to update the media.

Topics: death, murder-and-manslaughter, alice-springs-0870

First posted December 01, 2016 10:43:04