The Tuvalu Red Cross said water supplies in some areas would run out Tuesday and residents were warned against drinking water from wells, the BBC reported.
"It's not safe for consumption," Secretary-General Tataua Pefe said. "Some animals have died recently and we think it's because of subterranean water."
A New Zealand Air Force plane has flown to Tuvalu -- one of the smallest countries in the world, with a population of about 11,000 -- with water supplies and two desalinization units.
Tuvalu, which normally gets 8 to 16 inches of rainfall per month, hasn't had any significant rain in six months and meteorologists forecast the situation could persist until December, Pefe said.
Climatologists say the La Nina weather phenomenon is responsible.