New Zealand civil defense authorities have issued a tsunami warning after a magnitude 7.8 earthquake struck in the Pacific Ocean northeast of the country, the U.S. Geographical Survey said.

The USGS said the New Zealand earthquake struck at 7:03 a.m. on Thursday at the epicenter, 131 miles east of Raoul Island, part of the Kermadec archipelago, and was only 30 miles deep.

It also said a tsumani was possible, with eastern coastal areas of the North Island vulnerable, including the country's main city Auckland, arriving just before 9 a.m. local time, Reuters reported.

The U.S. Pacific Tsunami Center issued the tsunami warning, saying it did not yet know whether an actual tsunami had developed, but, if it had, it would hit East Cape in New Zealand within two hours and Auckland within three hours of the quake.

The tsunami may have been destructive along coastlines of the region near the earthquake epicenter. Authorities in teh region should take appropriate action in response to this possibility, the Center said in a statement.

No damages have been reported so far, but the National Crisis Management Center has been activated and Civil Defense said the fisrt wave to arrive will reach New Zealand at 8:52 a.m. on Thursday.

VIEW: New Zealand Earthquake: Breathtaking Tsunami Photos and Video [PHOTOS] [VIDEO]