A Chinese tourist trapped in the worst-hit town of Kaikoura receives interview of Xinhua News Agency, in Kaikoura, New Zealand, Nov. 14, 2016. [Photo/Xinhua]

Related: 'Utter devastation' after major quake

Wellington becomes a virtual ghost town with workers ordered to stay away from city

A powerful magnitude-7.8 earthquake pummeled central New Zealand on Monday, killing at least two people, damaging roads and buildings and setting off hundreds of strong aftershocks.

Emergency response teams flew by helicopter to the region at the epicenter of the tremor, which struck just after midnight some 90 kilometers northeast of Christchurch in the South Island, amid reports of injuries and collapsed buildings.

"It's just utter devastation, I just don't know ... that's months of work," New Zealand Prime Minister John Key told Civil Defence Minister Gerry Brownlee after flying over the coastal town of Kaikoura, according to Brownlee's Twitter account.

He described landslips in the area as "just horrendous". In a statement, Key said of the likely damage bill: "You've got to believe it's in the billions of dollars to resolve."

Power lines and telecommunications were down, with huge cracks in roads, land slips and other damage to infrastructure making it hard to reach the worst-affected areas.