A tourist driver who arrived from Australia early in the morning and immediately hired a rental car, fell asleep at the wheel when he crossed the centreline in South Canterbury and caused a head-on smash that killed his mother.

Hong Kong national Shu Na Lo, 27, had been studying in Melbourne when he brought his 66-year-old mother King Wai Vip and sister May Wong Kot to New Zealand for a holiday.

They left Melbourne at midnight on September 30 and arrived at Christchurch International Airport at 5am.

After hiring a car, they headed for picturesque Lake Tekapo.


But later that morning, on the State Highway 79 Geraldine-Fairlie road, with an open road 100km/h speed limit, it's believed that Lo - who has no memory of the crash - fell asleep and caused a head-on smash.

His mum was lying asleep, without a seatbelt, in the back seat.

She was thrown from the car in the impact and was found dead at the scene.

Lo's sister, a front-seat passenger, suffered serious injuries and was hospitalised in Christchurch for a month.

Christchurch District Court was told today that she is still in a wheelchair.

Lo appeared in the dock, with assistance of an interpreter, to be sentenced to disqualified from driving for 12 months and ordered to pay the victim in the oncoming car - 72-year old local man Graham John Dawson - $3500 in emotional harm repayment.

But Judge Jane Farish convicted and discharged Lo in relation to the careless driving causing death charge, and careless driving causing injury to his sister.

Defence counsel Miranda Rout had earlier asked Judge Farish to take mercy on Lo in what she described as a "terrible tragedy".

"There is no penalty that will ever exceed the guilt and grief that he will experience for the rest of his life that he caused his mother's death by an error of judgement, possibly of falling asleep at the wheel," she said.

The family is trying to raise cash to fly their mother's ashes back home through some "fairly complicated bureaucracy" in China.

The case comes after a spate of fatal crashes involving tourist driving, including a horrific smash last month that claimed the lives of three Hong Kong nationals outside Wanaka.

Driver Wing Fai Chan, 60, also known as Allan, and two female rear-seat passengers - Kwai Tei Chong, 61, also known as Connie, and Yin Wan Ng, 56 - died after their hired vehicle collided with a truck and trailer unit on State Highway 6 near Luggate, in the Wanaka area on November 6.

The New Zealand Transport Agency is working with the Ministry of Transport, police, local councils, the Automobile Association and the tourism sector to target tourist hotbeds in the South Island.

They are making sure rest areas and scenic spots popular for photographs are safe to negotiate and include clear road signage.

Also last month, Chinese driver Yichen Sun, 27, whose rental car collided with another vehicle near Queenstown was convicted in what a judge said was a "classic case" of why tourists should sit a driving test.

"It's a classic case of why people need to have examinations done before taking control of powerful rental cars on New Zealand roads," Judge Kevin Phillips said at Queenstown District Court.