A second South Pacific community is suffering a severe water shortage due to an ongoing drought crisis.
Tokelau declared a state of emergency late on Monday, following a similar move in neighbouring Tuvalu, where water is already being rationed.
A New Zealand-administered territory of three islands, Tokelau's 1,400 people have less than a week's drinking water left.
The lack of rainfall is blamed on the La Nina weather pattern.
Officials said Tokelau had run out of natural fresh water and was relying solely on bottled water.
New Zealand Foreign Minister Murray McCully said other islands in the South Pacific were also reporting water shortages.
Parts of Samoa have begun rationing water.
He said New Zealand was rushing to assess the situation throughout the region, amid fears the crisis could escalate.
New Zealand was "making sure we deal with the drinking water issue most urgently", he said.
A New Zealand Air Force plane landed in Tuvalu on Monday carrying containers of water and desalination units.
Tuvalu, one of the world's smallest independent nations, with a population of about 11,000, lies about halfway between Australia and Hawaii. Tokelau is about 500km (310 miles) to the east.
Impact on crops
Mr McCully said the situation was urgent in parts of Tuvalu.
He said there was less than a week's supply of drinking water on Funafuti, the main island of Tuvalu.
"I understand one of the other outlying islands, Nukulaelae, has a more urgent shortage and there is a desalination plant on the way there," Mr McCully said.
"There are going to be some flow-on effects here, clearly this is having a severe impact on crops, so there's likely to be a food shortage as well."
La Nina causes extreme weather, including both drought and floods, and was blamed for floods in Australia, South East Asia and South America in late 2010 and early 2011.
David Hebblethwaite, a water conservation expert with the Secretariat of the Pacific Community, said Tuvalu had experienced low rainfall for the past three years and there had been no precipitation at all for seven months.
He said Funafuti and Nukulaelae both lacked groundwater supplies, making them dependent on rainfall collected from the roofs of homes and government buildings.
Mr Hebblethwaite said the islands may also need extra medical supplies if water shortages lead to sanitation issues and consequent health problems.