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WELLINGTON, Jul 7 (Reuters) - New Zealand civil defence authorities said they expected stronger than normal ocean currents and a possible increase in the size of waves around the eastern coast but no wall of water after a magnitude 7.8 earthquake struck in the Pacific Ocean north east of the country.
A tsunami warning was issued for eastern coastal areas of the North Island, including the country's main city Auckland, with the first surge expected just before 9 a.m. local time (2100 GMT).
However, the U.S. Pacific Tsunami Center, which issued the original warning after the quake, later cancelled its warning, but reported waves were 2.2-2.7 feet (68-84 cm) high around Raoul Island, the main island in the Kermadecs.
New Zealand civil defence maintained a warning that people should stay out of the water and away from beaches in the target areas.
"We might get quite extreme currents, so it is a threat to boats, but we're not anticipating damage to land," Clive Manly the civil defence controller for the Auckland region, told radio New Zealand.
He said it was possible that waves of up to a metre above normal heights might occur.
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, the USGS said.
The Kermadec Islands are uninhabited except for science and conservation teams, and sit around 1180 kilometres north east of New Zealand.
They sit in a geologically active region of the South Pacific where the Pacific and Indo-Australian tectonic plates meet, and large earth tremors are not unusual.
New Zealand has been more alert to earthquakes since the South Island city of Christchurch, was struck by two devastating quakes in September last year and in February this year. The latter killed 181 people and caused an estimated NZ$15 billion of damage.