The president of the low-lying Pacific atoll nation of Kiribati said Thursday his country may already be doomed because of climate change.

President Anote Tong said communities had already been resettled and crops destroyed by sea water in some parts of the country, made up of 33 coral atolls straddling the equator.

Tong was one of several international figures in New Zealand's capital to promote action on climate change for World Environment Day.

Although scientists are still debating the extent of rising sea levels, Tong told a press conference that changes were already obvious in his country of 92,000 people.

"I am not a scientist but what I know is that things are happening we did not experience in the past," Tong said.

"We may be beyond redemption, we may be at the point of no return where the emissions in the atmosphere will carry on to contribute to climate change to produce a sea-level change that in time our small low-lying islands will be submerged," he said.

"Villages that have been there over the decades, maybe a century, and now they have to be relocated.

"Where they have been living over the past few decades is no longer there, it is being eroded."

He said at international meetings others had argued that measures to combat climate change would hurt their countries' economic development.

"In frustration, I said, 'No, it's not an issue of economic growth, it's an issue of human survival.'"

In the worst-case scenario, Kiribati would be submerged by the end of this century and Tong said he wanted help from other countries to resettle his people.

Scientists gathered by the UN in the Intergovernmental Panel on Climate Change say emissions of greenhouse gases would need to be capped by 2015 if global temperature rises are to be limited to two degrees Celsius.

Even restricting temperature rises to two degrees would doom Kiribati and some other island nations, United Nations Environment Programme (UNEP) executive director Achim Steiner said.

"At two degrees of global warming we are already destroying the places that people have called their homes for hundreds, sometimes thousands of years," he added.

Steiner called for World Environment Day to be seen as a rallying point for getting proposals to limit global climate change back on track.

"Unless we get back to the levels of public engagement this year we had last year, I worry that we will not have the political will in the international community to reach an agreement," he told AFP.

The focus of attempts to reach a global deal to replace the Kyoto plan to reduce greenhouse gas emissions moved to Bonn, Germany, this week where 2,400 negotiators are trying to hammer out an agreement to be signed by the end of next year.

Steiner said governments and individuals should not ignore climate change because of current crises over soaring food and oil prices.

"What we are saying is 'take a breath, but don't sit back because the situation is actually worse than we thought two years ago,'" Steiner said.

New Zealand was chosen to host World Environment Day events this year because it is one of the first countries to state the aim of becoming carbon neutral.