A Lumsden man is calling for a crackdown on tourist-driver regulations after a Japanese doctor fell asleep at the wheel and hit him head-on.

Dave Miller said it was a miracle he, his wife and teenage daughter were not killed or severely injured in the Lindis Pass smash on Boxing Day.

The man who hit him, Kansei Uno, 54, had been travelling for almost 24 hours when the crash happened.

Uno was convicted in the Dunedin District Court yesterday of four counts of careless driving causing injury and ordered to pay the Millers $15,000.

The defendant arrived in Auckland with his girlfriend, Tomoko Koyama, on December 26 and had a two-hour layover before flying to Queenstown.

There they rented a car and immediately began the drive to Mt Cook.

"I have never had a person who was prepared to drive after travelling halfway around the world," Judge Kevin Phillips said.

After two hours, Uno began to feel drowsy and pulled over for a nap.

But the 15-minute sleep was not enough to make a difference.

At 4.30pm, Uno veered on to the gravel strip on the left of the road before waking and swerving to correct his mistake, skidding into oncoming traffic.

Miller, who was driving with his wife and teenage daughter, took evasive action.

He steered into the opposite lane but Uno returned to his lane and they collided at 80-90km/h, the court heard.

Koyama, who was asleep at the time, suffered broken vertebrae and required surgery.

The Millers sustained extensive bruising and their daughter broke a rib and was left with lower back pain.

Miller said he did not hold a grudge against Uno but called it a "ridiculous decision" to get behind the wheel after nearly a whole day of travel.

He hoped Uno went back to Japan and educated others about the pitfalls of driver fatigue.

"When is the New Zealand Government going to act on the issue of foreign drivers driving on our roads?" Miller asked.

"It is ludicrous that my 18-year-old daughter has taken three years to obtain a full licence and experience with New Zealand roads and regulations, yet an overseas tourist can fly halfway around the world and obtain a rental car on arrival without an adequate rest.

"They then display poor decision-making and inadequate driving skills causing death and mayhem to innocent other people on out roads.

"How many more lives need to be lost or put at risk before action is taken?"

Uno's counsel Cate Anderson said her client was originally scheduled to stay in Queenstown rather than make the long drive immediately, but a flight cancellation had forced a change of plans.

"Dr Uno was devastated by what occurred," she said.

Judge Phillips struggled to understand how someone so intelligent made such a woeful decision.

The court heard the defendant was an associate professor at the University of Tokyo School of Medicine, specialising in computational diagnostic radiology.

"An educated person should recognise the risk and stop driving," the judge said.

"He let himself entirely down, in my view."

Uno told his lawyer he would be forced to resign if news of the crash was picked up by Japanese media but Judge Phillips granted applications to photograph the defendant and said the man's employment was a matter for his bosses, not for the court.

As well as the reparation ordered, Uno was banned from driving for a year.