UPDATED: 4:39 PM

 A reporter at the scene said there were still queues near the cordons.

State Highway 1, near Pohuehue has been closed after police shot a man who was approaching officers with a weapon. Photo / Brett Phibbs

Southbound traffic was being diverted to SH16 via Woodcocks Rd.

Northbound traffic was being diverted to Kahikatea Flat Rd at Silverdale and then through to SH16.

Motorists reported traffic jams on the detour routes.

One reader reported queues near Waitoki, another confirmed it took an hour to get from Silverdale to the SH16 intersection on Kahikatea Flat Rd, Waitoki.

NZ Transport Agency Auckland Transport Operations Centre manager Rua Pani earlier said State Highway 16 was the only alternative route for north-south traffic. There was no north-south access via the Hibiscus Coast Highway or east coast roads.

Motorists were advised to leave State Highway 1 at Silverdale or Warkworth to get on to State Highway 16. Motorists could continue on State Highway 1 north to reach the beachside communities at Orewa and Whangaparaoa and south to reach Warkworth, but there was be no through traffic.

This afternoon Pani thanked people for understanding.

"We realise the inconvenience this will have caused for many road users and the significant impact it may have had on Easter travel plans.

"Many road users will want to get on with their travel plans all at the same time now, so we advise motorists to plan their journeys and to check the latest travel updates on the NZTA website and social media accounts before setting off."

The Auckland Motorway Alliance had planned road works tonight from 8pm to 8am on State Highway 1 from Oteha Valley to Silverdale but, in light of the delays today, they had been postponed until tomorrow, she said.

The Shooting

Police Minister Stuart Nash says he has been fully briefed by Police Commissioner Mike Bush.

Mr Nash is expressing sympathy to the man's family, while noting the impact on all those involved.

Police have given a detailed account of what happened, starting with a call shortly before 3am from a woman in the Auckland suburb of Onehunga.

She reported a man known to her was acting erratically and she left, fearing for her safety.

Police arrived at 3.10am to find no one there.

Twenty minutes later a rural police officer heading home stopped to check on a car parked on SH1 near Topuni with hazard lights on.

The driver speed away, the police officer followed and they both ended up stopped again, at which point the man allegedly threatened the police officer, who was still in his car, with a machete.

The man headed south on SH1 towards Puhoi at speeds of up to 150km/h with the car's lights off while the police Eagle helicopter watched on.

The car was spiked on SH1 near Mahurangi West Road at about 3.50am.

The first officers got out of their patrol car and the man came towards them with a machete.

Police say it is at this point that police fired shots.

The officers immediately administered first aid and called for an ambulance but the man, who is from east Auckland, died at the scene from his injuries.

"We trust police to make the best decisions in extreme situations and the effects of their actions will stay with them," Mr Nash says.

He expressed condolences to the young man's family as did Waitemata District Commander Superintendent Tusha Penny.

Supt Penny says police deal with complex, dynamic and fast-changing situations and must make split-second decisions.

"No police officer comes to work wanting to end up in a situation like this."

Police have launched two investigations into the shooting and have also notified the Independent Police Conduct Authority.

The man's body was taken from the scene mid-afternoon.

The matter has also been referred to the coroner.

The road is closed at Puhoi on SH1. Photo / Tess Nichol