Wellington, New Zealand: Evacuations were under way in New Zealand Friday after a tsunami warning was issued following a powerful 7.1 magnitude earthquake which struck before dawn off the east coast of the North Island.

An initial ‘potential’ warning was upgraded to a tsunami after a wave measuring 30 centimetres was generated near the sparsely populated East Cape about 90 minutes after the earthquake struck.

‘The first tsunami activity has arrived. Tsunami activity will continue for several hours,’ the Civil Defence organisation, responsible for national emergency management, said in a statement.

The warning covered the East Coast of the North Island and the upper South Island.

The shallow tremor was estimated at a depth of around 30 kilometres (18 miles) off the coast, according to the US Geological Survey.

It was centred 167 kilometres (103 miles) from the nearest main town, Gisborne, which has a population of around 45,000.

Radio New Zealand reported that residents in coastal areas of the East Cape region were being advised by local civil defence officials to evactuate.

Civil defence public information officer Sheridan Gundry said the emergency management centre has been activated.