The authorities in Vanuatu are concerned about the water supply after tropical cyclone Lusi brought heavy flooding to the country's north overnight.
The cyclone felled trees, damaged houses, roads and crops.
At least one person has died during the cyclone, reportedly from a falling tree.
Schools have been closed as it moves away from the Vanuatu island group to the south-east.
A senior officer at the disaster management office, Philip Meto, says he has received reports that some underground water supplies have been contaminated by flooding.
"Most communities are using underground water. Because there's a lot of flooding and a lot of flooded areas, this report we also get from the communities indicate that all the waters have been contaminated from the flood."
Philip Meto says the office will hold a meeting this morning to collate information from the provinces and brief stakeholders.
The Fiji Met Office says Lusi, which is still more than 700 kilometres from Nadi, is likely to be upgraded to a category 3 storm later on Wednesday.
Close to its centre it has winds with momentary gusts to 150 kilometres an hour.