A tropical depression is expected to have intensified into a category one cyclone by the time it reaches Samoa early tomorrow morning.
The depression - TD07F - is currently south of the French Pacific island of Wallis, where it has brought heavy rains and strong winds.
The public broadcaster in Wallis and Futuna said power had been lost in some places and the phone network was experiencing problems.
People are banned from going outside until 7pm.
The storm has also forced the cancellation of tonight's flight from Noumea.
On Futuna, which was struck earlier today, there has been no serious damage.
The system with gusts of up to 120 kilometres an hour is, this afternoon passing to the south of Wallis and heading east-northeast towards Samoa at a speed of 31 kilometres an hour.
The Samoa Meteorological Service said it was expected to be a cyclone when it passes close to Samoa's two islands tomorrow.
Samoa was already drenched after days of heavy rain. More rain and rough seas are forecast for this weekend.
Rain still causing problems in American Samoa
And there's been no let up in the rain in American Samoa with schools closing for a second consecutive day today.
The National Weather Service said it was monitoring multiple tropical depressions in the region.
The Service's Carol Maafala Baqui said a monsoon trough that had brought over 43cm of rain over the past two days to the territory is also attracting the depressions, particularly Tropical Depression 7F, which has the potential to become a cyclone.
"This Tropical Depression is now connected to the monsoon trough so keep in mind, we've seen from past experience, that as long as the monsoon trough is intact definitely it will pull these embedded low pressures along with it."