New Zealand Civil Defence has issued a marine tsunami warning for New Zealand after a magnitude 8.9 earthquake struck Japan on Friday, but said it does not expect it to pose a threat for people on land.

A wave of up to 1 meter may reach the coasts of the central and northern North Island from about 6:30 a.m. local time Saturday, but the first arrival was expected to coincide with a low tide.

The Pacific Tsunami Warning Center said in an 8:30 p.m. (NZ time) bulletin a tsunami warning was in place for New Zealand, Australia and most countries bordering the Pacific Ocean.

"The New Zealand Tsunami Expert Panel assessment is that this is a marine threat only for New Zealand," Civil Defence said just after 10 p.m.

"A Marine Threat means strong and unusual currents are possible in the sea, rivers and estuaries. No land threat is expected at this time," it added.

Past experience and tsunami models indicated that the largest impact would be a wave of up to 1 meter reaching East Cape northwards and from Kaipara northwards.

Waves would continue for several hours, and the first one may not be the largest, Civil Defence warned.

The last place expected to be hit would be Nelson, about 11:15 a.m. Saturday.

The Ministry of Civil Defence Emergency Management and scientific advisors were closely monitoring the situation to determine the severity of the threat to New Zealand.

People in New Zealand coastal areas were warned to stay off beaches and out of the water.