Fiji's prime minister says he fears Pacific island nations are "doomed" because industrialised countries appear set to reject a global climate pact at crunch talks in Paris in December.

Powerful polluting nations were willing to sacrifice the low-lying islands to rising seas rather than risk the economic growth that fuels their lifestyles, Prime Minister Voreqe Bainimarama said.

He said the UN-sponsored COP 21 talks appeared set to become an excuse for wealthy nations to pay lip-service to climate change, without taking meaningful steps to address it.

"I have yet to detect the necessary political will on the part of many of the industrialised nations to face up to their obligation to humanity to effectively confront this crisis," he told a climate conference in Suva on Wednesday.

"I very much fear that COP 21 will be a cop out."

Bainimarama, a former soldier who led a military coup in Fiji before winning elections last year, said he would be making his presence felt in Paris, demanding climate action.

"I won't be going to Paris wearing the usual friendly, compliant Pacific smile," he said.

"Standing shoulder to shoulder with the other island leaders, I will sternly remind the industrialised nations of their obligations."

COP 21 aims to unite the world's nations in a single, binding agreement on tackling climate change, with the goal of capping warming at two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels.

But Bainimarama said island states -- which contribute little to climate change but have borne its brunt -- appeared "destined to leave the French capital empty-handed".

"Unless the world acts decisively in the coming weeks to begin addressing the greatest challenge of our age, then the Pacific as we know it is doomed," he said.

"Doomed to suffer the most negative impact of the rising temperatures caused by the carbon emissions that have accompanied the industrial age."

Bainimarama said Pacific nations such as Kiribati, Tuvalu and the Marshall Islands could disappear beneath the waves completely.

Others, including Fiji, were losing coastline, arable land and facing increasing extreme weather events "that already come out of nowhere, kill our people and ravage our economies".

He singled out regional power Australia as a major part of the problem, calling on new Prime Minister Malcolm Turnbull to ditch the policies of his climate-sceptic predecessor Tony Abbott.

"Side with us in the Pacific against the proponents of coal and the climate change deniers in your own government," he urged Turnbull.

"You have shown leadership on this issue before. Now that you have the job of prime minister and can really make a difference, please show leadership again."