The Red Cross says the atoll of Nukulaelae, in Tuvalu, is very low on fresh drinking water and has requested government assistance.
In an information bulletin, the Red Cross says 90 per cent of the population of Nukulaelae is being rationed, with 40 litres of water per family per day.
It says several people, including children, are suffering from diarrhoea and vomiting, and about 50 per cent of the people don't boil their drinking water, despite awareness efforts to do so.
The Red Cross says the availability of water seems to be critical, which is impacting the local crops including giant taro, bread fruits and coconuts.
It says the Public Works Department estimates that with the rationed amount, the community will have a minimum of about two weeks with the remaining water.