A 29-year-old east Auckland man has been fatally shot by police after coming towards officers with a machete.
He was shot dead near Pohuehue, north of Auckland.
Waitemata District Commander Superintendent Tusha Penny told media the shooting was related to an earlier police callout at an address in Onehunga.
A female called police to report a person known to her had been acting erratically.
She left the scene because she feared for her safety.
Police were sent to the property about 3.10am, however no people or vehicles were there when they arrived.
About 20 minutes later, a rural police officer heading home from a shift saw a car pulled over with its hazard lights on State Highway 1 north of Auckland.
However, the car quickly drove off. The police car followed and the car then stopped again.
As the officer was about to get out of his vehicle the driver of the car got out and came around to the driver's door of the police car, wielding a machete and threatening the officer.
The officer quickly moved away and called for backup. The officer watched the offender from a safe distance.
The alleged offender then got back into his car and headed south on SH1 towards Puhoi.
Additional police resources, including the Eagle helicopter, were called on to help.
The driver was believed to have been travelling at speeds of up to 150km/h and at times with lights off, Penny said.
Police placed spikes on the road, which successfully stopped the vehicle near Mahurangi West Rd about 3.50am.
As the first officers got out of the police car, the man, still armed with a machete, approached police again.
Police fired shots as he came towards them. Officers immediately started first aid and called an ambulance, but the man died at the scene.
The man is from east Auckland, but police will not be able to release his name until he has been formally identified and next of kin informed, said Penny.
She was not able to confirm whether the dead man was known to police.
"This is a tragedy," said Penny.
She told media her thoughts were with the man's grieving family.
"We have ensured that Victim Support is available to them and we will support them through this process.
"We are also ensuring that the staff involved are being supported. No police officer comes to work wanting to end up in a situation like this."
The welfare of the officers involved is paramount, Penny said, and police are ensuring they're cared for.
"Every day police staff deal with situations that are complex, dynamic and fast changing. Our staff have to make split second decisions, in situations where there is risk to their lives and members of the public," she said.
Three inquiries into the shooting are underway - one criminal to establish whether any crime was committed, another to look at policy and practice within the police, and the final an investigation by the Independent Police Conduct Authority.
The death has been referred to the Coroner.
Police are conducting a scene examination.
"We thank the public for their patience in this matter," said Penny.
Pohuehue is between Puhoi and Warkworth.
A 27km section of State Highway 1 has been closed between Woodcocks Rd and Silverdale and police since about 4am and police and the NZ Transport Agency is are warning motorists to expect delays.
Police earlier said the road was expected to reopen about 3pm.
The coroner's car left the cordoned off area at 3.15pm and tow trucks were seen heading in about the same time.
Southbound traffic is being diverted to State Highway 16 via Woodcocks Rd.
Northbound traffic is being diverted to Kahikatea Flat Rd at Silverdale and then through to State Highway 16.
A no-fly zone has also been put in place.
The exact circumstances of what occurred remain unknown, but Radio New Zealand reported a motorist saw road spikes just before the offramp at Silverdale about 4.30am.
Police were stopping vehicles and letting them through one-by-one, the man told the state broadcaster.
Glen Foote, who lives on Woodcocks Rd about 1km from Warkworth, heard helicopters doing tight circles, followed by multiple sirens at 4am. The noise was coming from the west.
"It sounded like they were chasing somebody."
Warkworth resident Becky Watson said she also heard helicopters in the area at 4am.
"[They were] flying so low it woke me up."
Auckland Transport operations centre manager Rua Pani said traffic travelling in both directions was unable to use the Hibiscus Coast Highway or east coast roads.
"Motorists are advised to leave SH1 at Silverdale or Warkworth to get on to SH16.
"Motorists will be able to continue on SH1 north to reach the beachside communities at Orewa and Whangaparaoa and south to reach Warkworth, but there will be no through traffic."
Historical data for Easter holiday travel suggests traffic heading north will get heavy from 10am and be very heavy from midday.
"State Highway 16 is not designed for that volume of traffic so there will be congestion and delays."
The road has now been opened more than 12 hours after the shooting. Police announced the road was opened again just before 4pm.
Motorists are advised to follow diversions and expect delays.