Water, water everywhere: The lagoon at Tuvalu's capital atol, Funafuti.

Water, water everywhere: The lagoon at Tuvalu's capital atoll, Funafuti. Photo: Dean Sewell

AUSTRALIA has responded to an SOS from the tiny Pacific nation of Tuvalu, which is days away from running out of water.

The federal government has sent officials and 1000 rehydration packs to Tuvalu's hospital as other governments and the Red Cross donate thousands of litres of drinking water.

''We have less than four or five days' [supply],'' Tuvalu disaster co-ordinator Sumeo Silu told The Age.

''We are rationing water well below the United Nations refugee rate, with just 40 litres per household. An average household here has 10 to 12 people.''

Schools have closed and the government has declared a state of emergency.

Australian aid arrived on Wednesday in a New Zealand Hercules, which delivered water, money for fuel for a water supply truck and desalination plants.

The federal government is considering sending a military aircraft to help deal with the crisis.

Tuvalu Prime Minister Willy Telavi pleaded to the United Nations General Assembly in New York last week to act on climate change or Tuvalu would not survive.

''It's mostly climate change,'' Mr Silu said of the predicament. ''Normally this is our rainy season but there's no rain. Even our root crops have died from the salt.''

Rising sea tides have contaminated underground water reserves. It has not rained in six months and scientists have said a prolonged La Nina has caused drought.

Australia will also send technicians to repair broken desalination plants.

''Last year Australia built 600 rainwater tanks, with a capacity of 9 million litres, but at the end of the day, if it doesn't rain, the Australian government can't help that,'' said James Gilling, AusAid's acting deputy director-general for the Asia Pacific region.

Australia may face an influx of the world's first climate change refugees from Tuvalu, which has a population of less than 11,000, in coming years if a solution is not found.