A Red Cross official in Tuvalu says they have got drinking water to Nui island but more will be needed soon in the wake of damage caused by Cyclone Pam.
Nui was the worst hit of Tuvalu's islands with waves washing over it from both the ocean side and the lagoon side.
The IFRC's Olioliga Iosua says the flood waters were more than a metre high and have polluted the island's water sources.
She says Nui's population of more than 500 is being accommodated in church buildings, community halls or schools, while jerry cans of drinking water have been shipped in from Funafuti.
"But the projection is they will only last for two weeks, so we are planning to have other runs of water to the island until the tanks have been cleaned up and filled with water."