Auckland (Reuters): A powerful earthquake off the coast of Papua New Guinea caused a low level tsunami and knocked out power in parts of the Pacific island nation while tsunami warning was also issued for New Zealand early on Sunday.

The US Geological Survey reported that a 7.9 magnitude earthquake struck 46km east of Taron on Saturday (Sunday NZT). The quake was 103km deep. Deeper earthquakes tend to cause less damage than shallow ones.

The USGS initially said that the quake's magnitude was 8.0, but later lowered the strength.

The Pacific Tsunami Warning Centre (PTWC) said that there was a threat of a tsunami in Papua New Guinea and nearby areas. It also warned that tsunami waves reaching 1-3m high were possible along the coasts of Papua New Guinea , while waves in other areas, including the Solomon Islands, would likely be less than 0.3m high.

Felix Taranu, seismologist with the Geophysical Observatory in the capital, Port Moresby said, a tsunami measuring less than 1m hit the coast of the island of New Ireland shortly after the earthquake . There were no immediate reports of damage from the tsunami or the quake, though officials were still working to contact people on the island, he said.

The quake knocked items off shelves and caused a blackout in the town of Kokopo in northeastern Papua New Guinea . But there were no reports of widespread damage in the town.

Shortly after the quake, New Zealand's Ministry of Civil Defence & Emergency Management (MCDEM) issued a tsunami warning for all coastal areas, including the Chatham Islands.