At least two people died in the series of violent quakes, according to Prime Minister John Key.
The quake struck some 93 kilometers (55 miles) northeast of the city of Christchurch just after midnight local time on Monday, the US Geological Survey reported. It triggered waves of 2.49 meters above usual tide levels, the Pacific Tsunami Warning Center (PTWC) said.
Cain has generated reports to determine who may be impacted and will be working to contact them to provide assistance, where needed.