The advisory runs from Whangarei up to the Bay of Islands, and urges people in or near the water to move away.
Minister for Emergency Management Kiri Allan says as soon as the quake was felt off the Kermadecs the team's been monitoring what's happening, and how it applies to the North Island.
She says people should expect strong and unusual currents and unpredictable surges in affected areas.
Geonet seismologist John Ristau says, with the epicentre nine-hundred kilometres away from the North Island, we can be more prepared.
He says with this one we'll have more time, compared to the earthquake that happened overnight.