An earthquake with a preliminary magnitude of 8.1 hit off New Zealand on Friday morning, triggering a Pacific-wide tsunami alert, the U.S. Geological Survey and local authorities said.

The powerful quake struck at 8:28 a.m. local time near the Kermadec Islands of New Zealand at a depth of 19 kilometers, the USGS said.

The country's National Emergency Management Agency said the largest waves have passed and those who evacuated can now return to their homes. But it added people should remain vigilant and take extra precautions with regards to beach and ocean activities as strong and unusual currents and unpredictable surges will continue for up to another 24 hours.

In Australia, the Bureau of Meteorology said a 64 centimeter tsunami wave was recorded at Norfolk Island, off the east coast of Australia. The bureau said waves of 13 cm and 6 cm were observed in Fiji and Tonga, respectively.

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Following the quake, a tsunami alert of up to 1 meter was issued for a wide area of Pacific coast including Australia, Chile, Ecuador and Peru, according to the Hawaii-based Pacific Tsunami Warning Center.

Japan's weather agency said sea-level changes could occur on the country's coastline but there will be no tsunami.

Before the magnitude 8.1 quake, two powerful earthquakes also struck off New Zealand, triggering a small tsunami on the island country.

Following the first quake, which hit with a magnitude of 7.3 at 2:27 a.m., a tsunami of up to 28 centimeters was observed at the North Island.

The USGS upgraded the magnitude of the first temblor, which occurred 178 kilometers northeast of the North Island at a depth of 10 km, to 7.3 from an initial estimate of 6.9.

At 6:41 a.m., the second quake struck with a magnitude of 7.4 off the Kermadec Islands at a depth of 56 km.

In February 2011, a magnitude 6.3 quake rattled the South Island city of Christchurch, killing 185 people and injuring thousands.