Tropical Cyclone Yasi, which developed yesterday afternoon, is now approaching the northern islands of Vanuatu.
The Vanuatu Meteorological Service says the category 1 system is strengthening.
The northern islands are expected to experience winds of about 50 knots or 95 kilometres per hour, with gusts up to 130 kilometres an hour.
Rough seas and flooding are also forecast.
The Vanuatu Meteorological Service says the cyclone is expected to affect the provinces of Sanma, Torba, Penama and Malampa.
It's predicted that Cyclone Yasi may bring gale force winds to the southern Solomons later today or tomorrow.
It is expected to reach the Australian state of Queensland on Thursday.