Emergency response teams have flown to the epicentre of a powerful 7.8 magnitude earthquake in New Zealand, which has caused "utter devastation" according to the country's prime minister.
At least two people were killed and roads and buildings damaged in the earthquake, which set off hundreds of strong aftershocks.
The tremor struck 91km 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 Mr Brownlee's Twitter account.
He described landslips in the area as "just horrendous".
In a statement, Mr 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.
A tsunami warning that led to mass evacuations after the original quake was downgraded after large swells hit New Zealand's capital Wellington, in the North Island, and Christchurch.
Wellington was a virtual ghost town with workers ordered to stay away while the city council assessed the risk to buildings, several of which were damaged by the tremor.
Severe weather with 140km/h, gale-force winds was forecast for the area.
In pictures: The destruction from the 7.8 magnitude earthquake in New Zealand pic.twitter.com/8QljgN2tQH
— RTÉ News (@rtenews) November 14, 2016
Christchurch, the largest city on New Zealand's South Island, is still recovering from the 6.3 quake in 2011 that killed 185 people.
New Zealand's Civil Defence declared a state of emergency for the Kaikoura region, centred on a tourist town about 150km northeast of Christchurch.
Kaikoura, a popular spot for whale watching, appeared to have borne the brunt of the quake.
"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," Mr Brownlee said.
The Navy's multi-role vessel HMNZS Canterbury was heading to the area, he said.
Urban Search and Rescue (USAR) said a 20-person rescue team and two sniffer dogs had arrived in the town. A second team was on standby in Christchurch, USAR said in a statement.
Hours after the quake, officials said a slip dam caused by the quakes that had blocked the Clarence River north of the town had breached, sending a wall of water downstream.
"Residents are urgently advised to move to higher ground immediately," RNZ quoted a statement from the Marlborough District Council as saying.
New Zealand lies in the seismically active "Ring of Fire", a 40,000km arc of volcanoes and oceanic trenches that partly encircles the Pacific Ocean.
Around 90% of the world's earthquakes occur within this region.
