Two people are confirmed to have died after a powerful earthquake in New Zealand caused a series of aftershocks, causing damage to buildings and leading residents to evacuate their homes for higher ground to avoid tsunami waves.

Authorities said they were not yet declaring a national emergency, saying the regions are coping well.

The magnitude 7.8 earthquake struck the country's South Island just after midnight on Sunday, with the epicentre recorded 57 miles north-northeast of the eastern city of Christchurch.

Shortly afterwards a two-metre high tsunami was recorded in Kaikoura on the east coast of the South Island, with smaller but “very dangerous” waves later hitting the coast near Wellington, according to local weather site Weather Watch.

The Civil Defence authority advised South Island residents living on the east coast and those living on the nearby Chatham Islands to move to higher ground.

A 6.2 earthquake later struck northwestern Argentina, but there were no immediate reports of damage or injuries.

On Monday morning a strong new tremor with a magnitude of 6.2, struck New Zealand's South Island, the U.S. Geological Survey said.

Firemen gather at the corner of Wakefield and Victoria Streets after an earthquake in Wellington, New Zealand (Getty)

Helicopters with medical and rescue personnel are being sent near the epicentre of the quake, where it opened up snaking fissures in roads and triggered landslides.

St John's Ambulance Dion Rosario said in a statement: “We are starting to get reports of injuries from the earthquake area, including Culverden area and Kaikoura.

New Zealand Earthquake in pictures Show all 9 1 /9 New Zealand Earthquake in pictures New Zealand Earthquake in pictures A powerful earthquake struck in a mostly rural area close to the city of Christchurch but appeared to be more strongly felt in the capital, Wellington, more than 200 Km (120 miles) away AP New Zealand Earthquake in pictures Access to the ramp for the Bluebrige Cook Strait Ferry was cracked, after a 7.5 earthquake based around Cheviot in the South island shock the capital, in Wellington, New Zealand EPA New Zealand Earthquake in pictures Broken glass and debris covers part of the road on Featherston Street after an earthquake in Wellington, New Zealand Getty New Zealand Earthquake in pictures The 7.5 magnitude earthquake struck 20km south-east of Hanmer Springs at 12.02am and triggered tsunami warnings for many coastal areas Getty New Zealand Earthquake in pictures New Zealand Earthquake in pictures New Zealand residents standnear the top of Mt Victoria, the highest hill in Wellington Getty New Zealand Earthquake in pictures Ships head out into the harbour in Wellington, following an earthquake centred some 90 kilometres (57 miles) north of New Zealand's South Island city of Christchurch Getty New Zealand Earthquake in pictures New Zealand residents park cars near the top of Mt Victoria, the highest hill in Wellington Getty New Zealand Earthquake in pictures Amora Hotel guests gather in a carpark after an earthquake in Wellington, New Zealand Getty

“However, at this stage we do not have specifics.”

In Wellington, 200 kilometres from where the earthquake struck, residents said the shaking went on for about three minutes, and was followed by a number of strong aftershocks.

Elsewhere in the city the earthquake collapsed a ferry loading ramp, broke windows and caused items to fall from shelves, as well as forcing hundreds of tourists onto the streets as hotels were evacuated.

New Zealand Police said in a statement: “A number of aftershocks of a lesser magnitude have been experienced up and down the country. Police continue to remind members of the public to drop, cover and hold during any subsequent earthquake.

A large crack runs along Kaikoura Road about two hours north of Christchurch, after a major earthquake struck New Zealand (AP)

“There is a tsunami warning to the east coast of the North and South Islands. Police advise the public in these areas to get to higher ground or go as far inland as possible. Wellington residents should avoid the beaches and waterways.”

The earthquake comes five years after a 6.3 quake that struck Christchurch in 2011, destroying much of the downtown area and killing 185 people. It was said to be one of New Zealand's worst disasters, causing an estimated $25 billion in damage.

Memorial plaques mark the spot where each of the 2011 quake victims died, and the city's cathedral in the main square has been left half-ruined after it was deemed too dangerous to repair.

The Antipodean country lies on the volatile Ring of Fire on the Pacific rim which is known for erupting volcanoes and frequent seismic disturbances.