A motorbike passenger is the latest to die in a crash on Tuakau Bridge-Port Waikato Rd, about 10km north of Port Waikato. The crash happened at 2.23pm. The second person involved - believed to be the driver of the motorbike - was taken to hospital in a moderate condition.
The Serious Crash Unit is attending the scene.
Traffic is being diverted and motorists are advised to avoid the area if possible.
Authorities are pleading for drivers to take care and expect delays as thousands return to main centres from long weekend breaks this afternoon, with this year's Queen's Birthday Weekend road toll already ahead of 2018.
Motorists heading home to Auckland from the Coromandel should expect a slow journey, with traffic reportedly crawling along State Highway 2. It is expected to remain busy until 8pm.
Earlier this afternoon a crash between a car and a motorbike in Hamilton left one person in a critical condition and two others with moderate injuries.
The crash happened about 12.45pm, heading eastbound on State Highway 1, at the intersection of Grey St and Cobham Drive, next to Hamilton Gardens. SH1 was closed for over an hour.
Just before 3pm a bus and a car collided on the road to Waitomo Caves - but all the occupants escaped with minimal injury.
St John treated one person with minor injuries at the scene.
Police are warning motorists to take care over the remainder of Queen's Birthday Weekend. The road toll stands at five. The holiday period began at 4pm on Friday and ends at 6am on Tuesday.
This morning a person was killed when their car smashed into a shop in Papatoetoe in Auckland, while last night a person was killed in a crash in West Melton, Canterbury.
On Friday night a person died following a police chase in South Auckland.
And a man died on Saturday in a motorbike accident on a farm - but the incident will not be counted in the holiday road toll as it did not occur on a public road.
On Sunday a motorcyclist died after colliding with a car at Waitaki, Otago.
Queen's Birthday road toll ahead of last year
Last year there were two fatal crashes and 118 injury crashes reported, resulting in three deaths, 36 serious injuries and 122 minor injuries.
Of the crashes, 43 per cent involved single vehicles in which a driver lost control or ran off the road; 15 per cent were intersection collisions and 14 per cent were overtaking and or head-on collisions.
The most common driver factors contributing to crashes were losing control, alcohol, travelling too fast for the conditions, failing to give way and not seeing the other road user.
Police national road policing manager Superintendent Steve Greally urged drivers to "stay alert, be patient" and not to rush.
"The lives of you and your passengers are worth more than arriving a few minutes earlier," he said.
Police have been out in force and have a 4km speed tolerance, meaning any driver detected by a safe speed camera exceeding the area's posted speed limit by more than 4km/h will be ticketed.
They are focusing on highways and open roads that are popular holiday journey routes.
The NZ Transport Agency asked people to check its website for the latest travel information and traffic delays, including predictions of when traffic would be worst, based on last year's Queen's Birthday Weekend.
More tips for safe long-distance driving
• Drive with your headlights on and be seen.
• Increase following distances.
• Avoid travelling in bad weather if you can.
• If you're driving a long distance, take regular breaks and share the driving when you can.
• Don't attempt to overtake traffic unless it's completely safe to do so – it's not worth the risk.
• If you are towing or driving slowly, pull over regularly to let other vehicles pass.
• Plan your journey and prepare for delays.
