Cyclone season in this part of the world does not usually begin until November.
The Fiji Meteorological Service said Cyclone Liua, a category one, was west of Makira on Thursday morning, and was forecast to pass the southern islands before veering out to sea.
Its winds were about 65km/h, but these were expected to increase. The cyclone was forecast to become a category two later on Thursday, near Rennell Island.