No damage or injuries have been reported.
The quake, with a preliminary magnitude of 6.3, occurred at 3:16 p.m. about 155 miles northeast of Vanua Levu, the main tourist spot in Fiji's chain of islands, at a depth of 18 miles, according to the U.S. Geological Survey.
Fiji, a chain of 322 islands, is southwest of Hawaii and due north of New Zealand, between Australia to the west and Tahiti to the east.
The Hawaii-based Pacific Tsunami Warning Center issued a bulletin that said there was no Pacific-wide threat of a destructive tsunami, but that quakes of the size measured Tuesday could cause damaging local tsunamis.
Nilesh Kumar, technical officer at Fiji's Mineral Resources Department, said there had been no reports of any tsunami and no reports from anywhere in Fiji of shakes being felt.
Kumar said the department is maintaining a watch and is in communication with the warning center in Hawaii.
The U.S. Geological Survey initially reported a second quake nearby, much deeper and with a magnitude of 6.8. But the survey removed the second quake from its Web site soon after details were posted.
The survey says that when a large earthquake occurs it is common for seismological equipment in the area to incorrectly record multiple temblors, and that such glitches are quickly corrected on its Web site.