A strong earthquake jolted the central North Island early on Saturday.

Geonet said the 'severe' magnitude 5.9 quake happened about 5km southwest of Taumarunui at 4.51am.

The earthquake was 9km deep and the intensity was severe.

The quake was reportedly felt across much of the North Island, including Auckland, and as far as the top of the South Island.

By 6am, nearly 23,000 'felt reports' had been filed to GeoNet.

At least seven aftershocks, ranging between magnitude 2.7 and 3.7, followed.

Fire and Emergency New Zealand said far it had received only a sprinkler-related callout stemming from the big quake.

Minor slips reported

Manawatū-Whanganui Emergency Management Group urged motorists to take care while driving after minor slips were reported in the area.

"Emergency services and roading crews are assessing the situation, but a fuller view of any impacts is unlikely to be available until daylight," it said.

No injuries or other damage had been reported.

The Emergency Management Group expected aftershocks to continue throughout the morning.

"If people feel them, they should drop, cover, and hold. If you are in bed, the best thing to do is to stay there and cover your head and neck with a pillow."

'Strong and long' in the lower North Island

The earthquake felt like it would not end in Whanganui, according to a resident in the suburb of Springvale.

Cushela Robson described the tremor as a very strong, prolonged rolling motion.

"I thought, should I get out of bed? And if I did, could I stand? So I thought, no, probably, because I grew up in Wellington, I thought, no, I think it's probably better to stay in bed."

"Even when I did get up I had to be quite careful, because the movement was still quite strong."