New Zealand civil defence authorities cancelled a tsunami warning on Thursday but warned of possible stronger than normal ocean currents around the east coast of the country after a magnitude 7.8 earthquake struck in the Pacific Ocean north east of the country.

It said a tsunami was generated by the earthquake around the Kermadec Islands, around 1180 kilometres (737 miles) north east of New Zealand, but scientists has advised it was of no threat to New Zealand.

"However, they expect that there will be unusually strong tidal surges and currents," the Civil Defence Ministry said in a statement.

The first surge had been expected at eastern coastal areas of the North Island just before 9 a.m. local time (2100 GMT), but there were no reports of unusual activity.

The U.S. Geological Survey said the quake struck at 7:03 a.m. on Thursday (1903 GMT on Wednesday) at the epicenter, 131 miles (211 km) east of Raoul Island, part of the Kermadec archipelago, and was only 30 miles (48 km) deep.

A small research team on Raoul Island, the main island in the group was reported safe and well.