Pacific island leaders insist climate change, not China, will top the agenda when they meet in Tuvalu this month as Western-aligned nations push to curb Beijing's growing influence in the region.

Once regarded as a sleepy backwater of the diplomatic world, the islands are now a hotbed of aid projects and charm offensives as anxiety over China's presence grows.

Australia has labeled its campaign the Pacific Step-Up, New Zealand has the Pacific Reset and Britain the Pacific Uplift, while the US, Japan and France have also intensified their efforts to court the region.

But local leaders attending the Pacific Islands Forum (PIF) in Tuvalu from August 13 to 16 are wary their concerns will be sidelined if they become pawns in a wider power struggle.

The 16-member forum mainly consists of small island nations, along with Papua New Guinea, Australia and New Zealand. 

PIF Secretary-General Dame Meg Taylor said the forum, whose members collectively refer to themselves as the Blue Pacific, was at a pivotal moment in its history.

"While we are the subject of the geopolitical maneuvering and strategies of others, the Blue Pacific collective remains focused on charting our own destiny," she said.

The primary concern for island leaders - many of whom live in low-lying nations threatened by rising seas - is climate change.

In a pointed message to Australia's conservative government, Tuvalu Prime Minister Enele Sopoaga has warned Canberra's step-up strategy will fail unless it finally takes meaningful action to address the issue.

"They know very well that we will not be happy as a partner, to move forward, unless they are serious," he said.

Wesley Morgan, a lecturer in international affairs at the University of the South Pacific in Fiji, said Pacific leaders regarded climate change as a greater security risk and expected those operating in the region to respect their concerns.

He said there was particular disappointment that Australia was dismissive about an issue its neighbors see as an existential threat.

While Canberra had paid lip service to environmental concerns, Morgan said island nations were acutely aware that, in real terms, it was set to miss Paris emissions targets and had recently approved construction of a major new coal mine.