Local residents Chris and Viv Young look at damage caused by an earthquake along State Highway One, south of the township of Blenheim on New Zealand's South Island, November 14, 2016. [Photo/VCG]

One fatality occurred a property at Mount Lyford, north of Christchurch, on the east of the South Island, and the other at a reported collapsed property in Kaikoura.

TVNZ showed footage of Prime Minister John Key and Acting Civil Defence Minister Gerry Brownlee surveying the damage to Kaikoura from an air force helicopter.

"It's just utter devastation, I just don't know...that's months of work," Key told Brownlee and pilots.

Key and Brownlee estimated the clean up would run into the hundreds of millions of dollars and clearing the debris and blocked roads could take months.

Navy supply ship HMNZS Canterbury would support the ongoing response in the Kaikoura region, Brownlee said in a statement later.

The region had suffered extensive damage to essential connections and basic infrastructure.

"The widespread destruction caused by the magnitude 7.5 earthquake and subsequent aftershocks will take considerable time and resources to repair," said Brownlee.

"Our immediate priority is ensuring delivery of clean water, food and other essentials to the residents of Kaikoura and the estimated 1,000 tourists in the town," he said.

The New Zealand Defence Force was delivering the essential items on its NH90 helicopters and on board HMNZS Canterbury.