Some of the world's most vulnerable island nations appealed Monday for action to halt climate change that could cause them to disappear beneath the Pacific Ocean.


Meeting in the Tongan capital, Nuku'alofa, the leaders of tiny nations including Kiribati, Tuvalu, Nauru, Niue, the Cook Islands and the Marshall Islands said countries responsible for greenhouse gas emissions must act.

"It is very, very serious because if we don't do something now, we are gone. That's for sure," said the Premier of Niue, Young Vivian. "There's no two ways about it and we are scared."

The highest points on some of the atoll nations are often only a few metres above sea level.

They are already suffering severe damage from high tides and fresh water supplies are becoming contaminated by salt water.

There are fears they may eventually have to be evacuated and their residents settled elsewhere.

"The problem is huge and the voice of the Pacific Islands has been yelling for the past 15 or 20 years and nobody is listening," Vivian said.

He said there was little the island countries could do.

"I think if big countries can't make other big countries behave, what power have we got?"

The small island nations were meeting ahead of the opening on Tuesday of the annual leaders' summit of the Pacific Islands Forum, which groups Australia, New Zealand and 14 Pacific island nations.

Pacific island political leaders were at the United Nations General Assembly earlier this month to appeal for action on climate change and the threat of rising seas caused by melting polar ice.

Vanuatu's Foreign Minister George Andre Wells said a rapid reduction in gas emissions needed to occur within the next 10 to 15 years.

Rising sea levels would have a critical impact on agriculture, water quality and infrastructure development, he said.