Pacific island leaders will renew calls for meaningful action on climate change at a regional summit opening in Palau on Tuesday, amid fears rising seas will swamp their low-lying nations.

Many of the 15 nations represented at the Pacific Islands Forum (PIF) lie barely a metre (three feet) above sea level, and regard themselves as the frontline of climate change, an issue they say threatens their very existence.

While emissions controls and carbon footprints can seem like abstract concepts in the climate debate, Palau President Tommy Remengesau said Pacific island nations were already facing the reality of global warming.

"Climate change is causing the seas to rise at unprecedented rates, increasing the intensity of storms and threatening to wipe entire states off the map," he told the United Nations earlier this year.

This week's meeting seeks to maintain momentum from the 2013 summit in the Marshall Islands, where Forum nations signed the Majuro Declaration, committing them to ambitious targets for cutting greenhouse gas emissions and adopting renewable energy.

While such a move is largely symbolic, Pacific leaders said they wanted to set a "moral example" to major emitters.

They have followed up with a diplomatic push to reinvigorate the stalled climate debate, emphasising the need for immediate action at numerous international forums.

Major emitters such as the United States, China and India will attend the Palau meeting as observers.

Marshall Islands President Christopher Loeak said it was an opportunity to drive the message home once again ahead of a special UN summit on climate change in New York on September 23.

"Are we willing to let another decade slip away, standing idly by as the world's most vulnerable countries and people, including my own, fight a losing battle against the king tides and typhoons of a warmer world?" he said.

"Or will we instead stand together and say we are ready to embrace a carbon-free future, and to do it today?"

While climate change is the central theme of the four-day summit, a raft of other issues will be discussed including sustainable development, managing the $4.0 billion a year tuna industry and protecting marine life in the vast ocean territories belonging to PIF members.

The fate of Fiji, which was expelled from the PIF in 2009 after its military regime reneged on a pledge to hold elections, is also likely to be discussed, although readmission is unlikely before elections scheduled for September.