The Vanuatu Meterological Service says a tropical depression is heading towards its northern provinces and it's concerned the system may develop into a tropical cyclone within the next 24 hours.
A forecaster David Gibson says Torba and Penama are likely to receive at least 100 millimeters of rain and gale force winds if the tropical depression stays on its current course.
He says a marine warning has also been issued to vessels travelling between northern Vanuatu islands to seek safe harbour.
"At the moment it's still a tropical depression. The chances of it becoming a cyclone within the next 24 to 48 hours is moderate."
David Gibson says clouds from the system are also covering the southern provinces of Solomon Islands and they too can expect heavy rain and high winds. He says it's still too early to tell if the potential cyclone will hit Fiji.