The New Zealand defence minister, Wayne Mapp, says the threat posed by sea level rise was among the issues discussed behind closed doors during the French summit with Pacific leaders in New Caledonia.
The Noumea meeting was held amid tight security as the city is in the grip of unrest over the jailing of several unionists.
The third such French summit was downgraded after Nicolas Sarkozy pulled out, prompting several regional governments to send officials only.
France sent the foreign minister, Bernard Kouchner, to chair the summit, which Mr Mapp says dealt with three main points.
"Security issues, particularly illegal fishing, secondly economic issues and that's very much around growth and development - that's quite a challenge for quite a number of Pacific nations - and then the third issue, which is particularly pertinent to the atoll states , is climate change. Sea level has to rise only half a metre to a metre to seriously endanger a number of the states."
New Zealand's defence minister, Wayne Mapp.