Police say they are "devastated" by the Labour weekend road toll, which stands at seven, one fewer death than during the holiday weekend last year.

All the crashes were avoidable, national police roading manager Superintendent Paula Rose said.

"They all involved either speed, alcohol or crossing the centre line, the very things that we have been urging drivers to take particular care with," she said.

However, it appeared the vast majority of drivers did heed the police message as the roads had been "calmer and quieter".

The number of reported crashes were reduced by 25 per cent, she said.

"This is a very strong indication overall the roads are safer but this will be cold comfort to the families and friends of those seven people who lost their lives this weekend," Ms Rose said.

Police would remain out in force today.

"We may have lost this battle to stop people dying needlessly on the roads but the war will continue," she added.

The road toll rose to seven after a West Coast teenager was killed after she was flung from a ute last night.

Harmony Wihongi, 16, died after the Toyota Hilux left the road and crashed on State Highway 67, known as Fairdown Rd, just north of Westport, about 11pm yesterday.

She was critically injured when thrown from the ute and died at the scene, Sergeant David Cross of Westport police said.

The 16-year-old male driver fled the scene but was tracked down by police and arrested for drunk driving.

A 20-year-old Otago University student with a bright future was also killed.

Jessie McKenzie Lineham, of Invercargill, died after her Honda car collided with a Holden on SH93 in Southland about midday Saturday.

The crash happened about 15km east of Mataura, near Gore, on a stretch of the highway known as Old Coach Rd.

The 46-year-old driver of the Holden and his two children were injured in the crash, with one sustaining serious injuries, Senior Sergeant Dave Raynes of Invercargill police said.

The man was in Invercargill Hospital, while the 8-year-old boy and 11-year-old girl was flown to Dunedin Hospital.

The boy had a suspected broken leg, while the girl underwent surgery Saturday afternoon.

Ms Lineham had been studying towards a career in environmental science.

She had been awarded a Gold Crest award by the Royal Society for her high school paper on the effects of dairy farming on a waterway.

The work also earned her a Dexcel Dairy Future Scholarship Award, which funded a year of her university education.

Yesterday, a 74-year-old woman died after a Subaru Impreza collided with a Nissan Bluebird on a gravel road near Wanganui.

The accident happened just after 4pm on Kaikokopu Road in Brunswick, 11km north of Wanganui, police said.

The woman was a passenger in the Bluebird. The driver was taken to hospital with serious injuries.

Some of the five occupants of the Impreza received minor injuries, police said.

Early Sunday, a crash in Waikato which killed two people was believed to have involved speed and alcohol.

Emergency services were called to the scene on Rotowaro Road, west of Huntly, about 1.45am.

However, investigators believe the crash may have happened earlier as the area had a power cut about 1.15am.

The car appeared to have failed to take a slight bend and collided with a power-pole, which would explain the earlier power failure, district road policing manager Inspector Leo Tooman said.

A man, believed to be the driver, had been able to raise the alarm, he said.

A fourth person, who had been a passenger in the car before being dropped off in Huntly, was assisting police with their investigation.

Later that morning a truck driver died in a crash on State Highway 1 near the Conway River Bridge, near Kaikoura, at 8.30am.

On Friday, one person died and a second was injured in a head-on collision on SH2 at Matamau, near Norsewood in the southern Hawke's Bay about 8.15pm.

The lowest Labour weekend toll since records began in 1956 was three -- in each of the years 2002, 2003, 2005 and 2006.

The worst tally was 1978, when 16 were killed.

The official holiday period ends at 6am tomorrow.