The Labour Weekend road toll has risen to six after four people were killed in a crash in Gisborne tonight.
Emergency services were called to the two car collision on Matawai Road just after 10pm.
One vehicle caught fire, killing three people inside. An occupant of the other vehicle also died at the scene.
Earlier in the day a pregnant woman was killed in a car crash near Timaru.
The 24-year-old Timaru women died when the car her husband was driving collided with another vehicle near the intersection of State Highway 1 and Divans Road, north of Timaru, shortly before 3pm.
Her husband suffered serious injuries when he was thrown from the vehicle, while, their two children, aged four and five, have been treated for minor injuries.
Police are continuing to investigate the crash.
Meanwhile, alcohol and speed are believed to have been contributing factors behind a single vehicle crash that claimed the life of a teenager.
The crash occurred around 8.15pm yesterday on Plateau Road, Reporoa, after the driver lost control on a right-hand bend. The car skidded sideways, flipped and landed on its roof.
Annalese Bacon, a 17-year-old Taupo resident, died at the scene. Police say early indications are that she was not wearing a seatbelt.
The driver was taken to hospital with moderate injuries to his arm and another passenger received treatment for a minor cut to his head.
Inspector Kevin Taylor said the crash was completely avoidable.
"This is a tragic reminder of what happens when simple messages are not followed."
At about 11.15am police were called to a crash on the southern motorway in Manukau where a car had flipped onto its roof, causing traffic congestion.
A witness to the crash told ONE News police were looking for the driver, who had fled the scene.
A review of national crash-cause data shows the highest proportion of crashes during Labour Weekend are a result of poor observation, poor judgement, failing to give way, poor handling, alcohol and speed.
Police said they would be targeting these factors throughout the long weekend period, which started at 4pm yesterday and ends at 6am on Tuesday.
New speed cameras rolled out
Police are rolling out 45 new high-tech speed cameras to stop heavy vehicles getting away with breaking their speed limit of 90 kilometres per hour.
They replace an existing 31 mobile cameras that currently cannot detect the difference between a truck and a car or whether a vehicle is towing something.
AA spokesperson Dylan Thomsen said the new cameras are designed to ensure drivers of vehicles with attached trailers do not break the speed limit.
"There have been some drivers not obeying the lower speed when they are towing or in a truck and that makes our road riskier.
Thomsen said speed was particularly dangerous for these drivers because the distance required to stop safely is further.
As well as the cameras, a lowered speed tolerance has been put in place for the duration of the weekend, down to 5km over the speed limit, as opposed to the usual 10km speed tolerance.
Additional police patrols have also been put in place, covering the main highways and areas of risk.
State has also launched an initiative to target driver-fatigue, with 'Driver Reviver' rest stops along some of the country's main highways to encourage drivers to rest on long journeys.
Staff are handing out coffee, barbecued sausages, fruit and water in Putaruru, Lewis Pass, Ruakaka, Ohakea and Ealing throughout the weekend. There are also activities for kids, safety information and toilets.
Eight people were killed in crashes last Labour weekend, 17
seriously injured and 92 others also hurt.