A top South Island cop says bad driving is not the preserve of foreign tourists as local drivers are to blame for the majority of crashes and deaths.

Mid-South Canterbury area commander Inspector Dave Gaskin told the Herald claims by officers patrolling the region's roads that foreign drivers were causing the bulk of driving incidents on South Island highways were not correct.

A Twizel police officer today slammed "crap driving" on the region's roads saying 80 per cent of the tickets he had written on one of the country's most scenic southern highways had been given to overseas tourists.

READ MORE: Fatal Glenavy crash - 'Men would still be alive if one wasn't speeding'

Senior Constable Bruce Francis also urged motorists to give rental vehicles a wide swerve on the roads in case they came to an abrupt stop or suddenly pulled over to look at the scenery.

On Christmas Day a Timaru woman made a citizen's arrest after a driver from China overtook three cars and a bus on a blind corner near Tekapo.

But Gaskin said the Twizel officer and other local police were "shooting off at the mouth" about overseas drivers and unfairly maligning foreign and foreign-looking drivers.

"The majority of people killed on the roads in our country are locals," Gaskin said.

"We have a lot of Asians living in New Zealand and 90 per cent drive very well.

"Some of these guys in small areas will deal with a particular thing in their area and they shoot off at the mouth and are not quite correct.

"They [the officers] are suffering from tunnel vision."

A passenger has been treated by and ambulance after a safari tour vehicle rolled on the Chard Farm Road in Queenstown.

Gaskin said the officers who spoke out of turn would not be disciplined as they hadn't breached rules.

Gaskin said there were 120 complaints about bad driving across Canterbury yesterday, including 47 in mid-south Canterbury.

"Of the 47 I can guarantee the majority would not be rental vehicles and not be overseas tourists."

He denied 80 per cent of tickets were going to foreign drivers.

All tourists to the region were often left in awe by stunning vistas and tended to stop in places that were not ideal for photographs.

He said there were places designated for stopping along the route and those wanting a picture were encouraged to wait until they reached the lay-bys.

When it came to following distances, Gaskin said all drivers needed to allow plenty of space on the road irrespective of whether or not they belonged to a rental company.

The Canterbury inspector said there had been a dire 200 per cent increase in the number of deaths on the region's roads and pleaded for people to take their time and show patience ahead of some of the busiest traffic days in the year.

This year the Christmas-New Year road toll stands at seven.

The latest to die were two South Island drivers in a horror crash on the Waimate Highway on Boxing Day.

The two men killed in that crash have been named as Horton James Hill, 80, of Christchurch, and 31-year-old Matthew James Gilchrist, of Oamaru. They died at the scene of a crash between Carrolls and Stangers Rds shortly after 8.30am on December 26.