A horror weekend on New Zealand roads has left at least six people dead in eight major crashes, and several others fighting for their lives.

It has bumped the year's current road toll above last year's, and road safety experts say New Zealand may be on track to have its worst year in over a decade.

The run of tragedies began late on Friday night when an 18-year-old woman died in a single-car crash following a police pursuit in Christchurch. The fleeing vehicle smashed through a fence and hit a school building. Three men were taken to hospital.

On Saturday about midday two motorcyclists taking part in a charity ride for a sick child died in a Southland crash, while another was left fighting for his life in Dunedin Hospital.

Later in the day another motorcyclist died in a crash on Henderson Valley Rd in West Auckland about 3.20pm. Shortly after 4pm, yet another motorcyclist lost their life in a crash on the West Coast while taking part in the Tribute 29 Pike River Memorial Run.

Yesterday morning one person died in a car crash near Okere Falls in Rotorua. And last night emergency services were attending a major crash just south of Kawakawa involving multiple patients and three rescue choppers. Two vehicles flipped and SH1 was completely blocked.

Meanwhile, another car flipped into mangroves in Northland yesterday morning leaving one person seriously injured, and six people were taken to hospital yesterday afternoon following a serious crash in the Tasman district.

The latest Ministry of Transport figures for road deaths for the year to Friday of 325 was on par for the same time last year, but the horror weekend was sure to take it above.

Last year 378 people died on New Zealand roads, the highest since 2009, when 384 people lost their lives. The next worst toll was in 2007 with 421 dead.

AA road safety spokesman Dylan Thomsen said in the early years of this decade New Zealand saw a substantial improvement in road safety, reaching a low point in 2013 when 253 died.

Since then the country had been on a "steady climb" back up.

"This has been a horrific weekend for all the families and friends who have lost their loved ones, and even worse is it has happened to more than 300 others this year.

"It is extremely sad and frustrating for everybody involved in road safety. We are not seeing any improvement in the number of people being killed from last year."

Thomsen said there was no simple answer as to why more people were dying on our roads.

"The population has increased, more people are driving, more kilometres are being travelled and more freight moved on the roads, but that does not account for all of that increase."

While other countries had also seen little improvement in road safety, New Zealand was one of the worst.

"A lot of developed countries have either stopped having improvements or seen some increases, but New Zealand has definitely been the worst in terms of the climb from 2013 to where we are now."

The year's deaths include 46 involving motorcycles, up from 38 last year.

Thomsen said he could not say what the increase was down to, but as the weather improved generally more people were out on motorbikes.

One of the four motorcyclists who died this weekend was doing it in memory of those killed in the Pike River explosion.

The rider was taking part in the Tribute 29 Pike River Memorial Run and died at the scene of the crash on Lower Buller Gorge Rd.

Sonya Rockhouse had two sons working in the Pike River mine - Ben - who died, and Daniel, one of the two survivors.

She was "incredibly sad" to hear of the motorcyclist's death and said she was thinking of the rider's family.

"These people were doing something to help us and pay tribute to us and for a life to be lost is incredibly sad," she said.

"I have been thinking about their family, we understand how they feel."

New Zealand Motorcycle Safety Consultants CEO Allan Kirk said the weekend deaths showed motorcyclists needed to improve their skills.

"Too many Kiwi motorcyclists do not have the skills necessary to operate a difficult-to-ride and powerful machine that leaves the rider vulnerable in a crisis. And many of these skills are not being taught to Kiwi motorcyclists.

"Too many riders know nothing about riding survival skills, especially the most essential one of how to reduce the chances of injury in a motorcycle crash."

Dog and Lemon car review website editor Clive Matthew-Wilson said the Government needed to take prompt action to bring the road toll down.

"All motorcycle riders should be put through a far tougher test, one that measures awareness and reaction times."

He also said the Government needed to speed up the installation of median barriers.

"Median barriers prevent 100 per cent of head-on collisions and it's a complete myth that they're unsafe for motorbikes."

National road policing manager Superintendent Steve Greally said all three motorcycle crashes were being investigated by the serious crash unit and it was too early to comment on the circumstances.

"However, with variable weather conditions across New Zealand today, our plea to all road users is to pay attention and make safe decisions.

"All road users need to be in a position to react quickly and safely if someone makes a mistake in front of you.

"We need motorcycle riders not to take risks."

Going too fast for the conditions or attempting unsafe passing manoeuvres could have tragic consequences – both for riders and those sharing the road with them, he said.

"And other motorists also have a part to play – we know motorbikes can be hard to see, so all drivers should be looking twice at intersections and before changing lanes.

"Too many people have lost family members and loved ones this weekend already.

"Regardless of whether you're on a motorbike or in a car, if you're out on the road today, please look out for each other so no more lives are lost unnecessarily."

DEADLY WEEKEND

Friday, 11.15pm:

An 18-year-old woman died and three others were taken to Christchurch Hospital after a fleeing driver smashed through a fence and crashed into a building at Christchurch East School. The driver remained at large last night.

Saturday, 12.45pm: Two motorcyclists died and a third suffered critical injuries in a crash at Isla Bank, northwest of Invercargill. They were on a fundraising ride for an unborn child with a heart condition.

Saturday 3.20pm: A motorcyclist died in a single vehicle crash on Henderson Valley Rd in West Auckland after careering into a ditch.

Saturday, just after 4pm: A motorcyclist died in a crash on Lower Buller Gorge Rd on the West Coast. The man was taking part in a memorial ride for the Pike River miners.

Sunday 7am: One person died in a crash near Okere Falls in Rotorua. The accident happened on SH33 and left another person seriously injured.

Sunday 10.15am: A person was seriously injured after their car rolled off SH12 in Northland, landing upside down in a stand of mangroves.

Sunday 4pm: Six people were taken to hospital after a serious two-car crash on the Coastal Highway at Redwood Valley in the Tasman district.

Sunday 4.30pm: Three people were transported to Northland Base Hospital - two of them critically injured - after two cars flipped in a serious crash that blocked SH1 in Northland.