The President of Palau Tommy Remengesau says the Pacific Islands Forum needs to come together on the issue of climate change.
The small island states in the Pacific want carbon emission targets that would lead to an increase in temperature of no higher than 1.5 degrees above pre-industrial levels.
Australia and New Zealand are advocating a two degree limit.
Tommy Remengesau says time for talk has ended and urgent action is needed which would require greater unity.
"This is the challenge facing regionalism is what can we do that brings out the most good for everybody, especially when it comes to matters of life and death and survival, sustainability. Those issues are the very reason why there is a Pacific Islands Forum. If you don't believe in those then there really should be no solid effort here."
Kiribati's Tong says Forum could split over climate change
The President of Kiribati, Anote Tong, says the Pacific Islands Forum could split over the climate change issue.
He says this may be necessary to reach a uniform position on climate change.
Islands Business says the Kiribati President has told the media in Port Moresby where the Forum is holding its annual summit that either Australia would have to leave the Forum, or others, such as Kiribati, would go.
Fiji's leader Frank Bainimarama is not attending this week's meeting in protest at the presence there of New Zealand and Australia.
New Zealand is "doing the right thing"
The New Zealand Prime Minister, John Key, says he is comfortable with his country's work on climate change despite mounting pressure for Pacific Island Forum leaders to do more.
"You can understand absolutely why countries that are very low-lying would have concerns about anticipated rises in sea-levels. And of course they would do everything they can to advocate for that.
"But New Zealand doesn't look to try and close them down or run away from the targets we've set and the actions that we've taken. I actually genuinely believe that we are doing the right thing."
Meanwhile, the Australian government has said it cannot do more to cut greenhouse gas emissions because it would be too costly.
The country's climate ambassador, Peter Woolcott, said its goal of reducing its emissions by between 26 and 28 percent below 2005 levels in 15 years was "an ambitious target".
The Forum leaders meet on Thursday for their retreat.