A magnitude 5.9 earthquake was felt across much of the North Island and parts of the South Island at 4.02am on Friday.
GNS Science says its epicentre was in the Taupo region, within 5km of Atiamuri, at a focal depth of 150km.
It says the quake was unlikely to have caused much structural damage to buildings.
Seismologist Bill Fry says the tremor was significant, but should not cause panic.
It was the second earthquake in the region in 24 hours; another at 6.19pm on Thursday measured magnitude 3.5. It was 5km deep and was 40km east of Taupo.