The New Zealand earthquake Tuesday night was the biggest hit the northern part of the country "in a long time," but the impact had been limited due to depth and distance offshore.

The deep 7-magnitude NZ earthquake struck off the Taranaki coast at a depth of 230km at 10:36pm, according to GeoNet. The US Geological Survey is putting the tremor at 6.2. The centre of the tremor was at 60km southwest of Opunake.

No major damages were reported overnight following the earthquake, which was followed by minor aftershocks.

Memories of the Christchurch quake

It will be recalled that a 6.3-magnitude quake shook Christchurch in February last year. It caused major damages and left 185 people dead.

Although Tuesday's earthquake was deep at 230km, its energy travelled efficiently to the surface, causing things to wobble on the ground.

"The result has been that it's been felt very, very widely across central New Zealand areas," GNS Science seismologist Lara Bland told Radio New Zealand. She added it was the biggest quake to be felt in the North Island for the past 100 to 120 years.

While the magnitude suggests considerable strength, the quake was deep and its distance offshore had limited the impact by the time it hit the surface.

Strong, but force too far away

"With a depth of 230km everyone on the surface is already at 230km or a greater distance away from the earthquake's focus, so the ability for it to have caused major damage is lessened," she told Fairfax NZ News.

Taranaki civil defence senior emergency management officer Shane Briggs told AAP the department receved no reports of damages or injuries Tuesday. He said his department, particularly emergency services, would continue to assess the situation overnight.

"It wasn't really a major sort of shake, it was a long, slow rolling, things wobbled around a bit, so there'll probably be small incidental damage," Mr Briggs said.

New Zealand lies on the "Ring of Fire," in which volcanic eruptions in the basin of the Pacific Ocean happen frequently. As a result, Kiwis are subjected to up to 15,000 minor tremors a year.

From tremors to floodwaters

Meanwhile, the North Island is expected to experience more inconvenience Wednesday with heavy rains forecasted on the area. Heavy rain caused flash flooding to some areas in Auckland and the eastern Bay of Plenty before the quake struck Tuesday. A low pressure system is bringing all the rain.