The Police Department of New Zealand, has revealed that a gunman killed two people and wounded six others in central Auckland Thursday, hours before the New Zealand city hosted the opening match of the 2023 FIFA football World Cup.

A 24-year-old shooter tore through the waterfront construction site with a shotgun in the early morning, plunging the busy centre of New Zealand's largest city into lockdown.

Prime Minister Chris Hipkins said the gunman also died at the scene and there was no national security threat, so the marquee tournament could go ahead as planned.

Police believe the attack was not directly linked to the World Cup, nor was it politically or ideologically motivated.

But the gunman was known to police and said to have had a history of family violence and mental health issues.

Police said he had been subject to a home detention order but had an exemption to work at the site. He did not have a license to own a firearm.

Police Commissioner Andrew Coster said there had been "nothing to suggest he presented a higher-level risk".

Aucklanders had circled today's date as the start of a month-long festival of football that would showcase their city and country to the world.

Instead, they were woken by the sound of police sirens and helicopters thudding overhead.

Inside the building site, workers reportedly hid or attempted to barricade doors to save their lives.

Police Commissioner Coster said it was a "shocking and traumatic event for those people who came to work and found themselves in the middle of an armed emergency".