New Zealand has been hit by a 5.6 magnitude earthquake off North Island, USGS reports.

It happens hours after Japan suffered a 7.4 magnitude jolt and a series of aftershocks off the Fukushima coast which unleashed tsunami waves.

The earthquake, initially estimated at magnitude 6.3, was registered at a depth of 37km (23 miles) and centered off the coast of North Island, some 121km (75 miles) from Palmerston North.

More details to follow.