Fiji' Mineral Resources Department has issued a tsunami warning for coastal areas near Labasa and the north west coast of Viti Levu.
Fiji TV reports that this follows an undersea earthquake measuring 6.8 on the Richter scale 160km north west of Labasa this afternoon.
No reports of damage have been received yet.
But a spokesman for the Mineral Resources Department, Lasarusa Vuetibau, says an undersea earthquake of this type which occurred 29km below the sea can generate tsunamis.
He says people living along coastal areas should be on alert night and be ready to evacuate.