New Zealand 7.4 earthquake, Tsunami follows powerful tremor. (BBC).
The US Geological Survey said the magnitude-7.8 quake hit just after midnight (11:02 GMT on Sunday), some 95km (59 miles) from Christchurch.
The tsunami arrived in the north-eastern coast about two hours later. Officials said the first waves may not be the largest, with tsunami activity possible for several hours.
Residents were warned to head inland or for higher ground along the coast.
Terrifying.A gauge at Kaikoura, 181 km (112 miles) north of Christchurch, measured a wave of 2.5m (8ft 2ins), according to Weatherwatch.co.nz.
Smaller waves are said to be arriving in Wellington and other areas, the website said.
But the ministry of civil defence has said the highest waves, which could be as tall as 5m are expected between Malborough, the north-eastern tip of the South Island, and Banks Peninsula, just south of Christchurch. More here and First causalities reported here in live report.