Samoan prime minister Tuilaepa Sailele has attacked climate change deniers as "utterly stupid", urging Australia to cut its carbon emissions.

Mr Sailele, speaking during a visit to the Lowy Institute, a foreign policy think-tank in Sydney, said climate change was a "disaster" threatening Pacific Island nations.

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"We all know the problem, we all know the solutions, and all that is left would be some political courage, some political guts, to tell people of your country there is a certainty of disaster," Mr Sailele told the crowd.

"So any leader of any country who believes that there is no climate change, I think he ought to be taken to mental confinement. he is utterly stupid. And I say the same thing to any leader here."

His speech comes as conservative MPs up the pressure on new Australian prime minister Scott Morrison to increase investment in coal and gas and drop the commitment to Paris targets to reduce emissions.

Mr Morrison has also been criticised for skipping next week's Pacific Islands Forum leader's meeting in Nauru.

Criticism of China loans 'patronising'

Samoa's prime minister also took aim at countries for patronising Pacific Island nations with their concern about debt problems and criticism of China's surging lending in the region.

China has spent $1.3 billion on concessionary loans and gifts since 2011 to become the Pacific's second-largest donor after Australia, stoking concern in the West that several tiny nations could end up overburdened and in debt to China.

He said China was not to blame.

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"We should not accuse the lender itself," Malielegaoi told Reuters in an interview when asked about the region's growing debt to China.

"It's up to the country itself to ensure that it sets down guidelines to borrow," he said. "The only reason why countries have not been able to pay is because they did not have proper financial strategies."

China has said it is supporting development in a region where it is needed.

But the debt issue has become a prominent concern since China took possession of a Sri Lankan port as Colombo struggled to pay its dues.

Australia in particular, which has long viewed the Pacific as its backyard, has been critical of some Chinese aid projects, and a former foreign minister has warned that the lending could undermine the long-term sovereignty of recipients.

Malielegaoi said unidentified "traditional" partners had "left the neighbourhood, even if momentarily" and returned to find the region more hotly contested.

"Our partners have fallen short of acknowledging the integrity of Pacific leadership and the responsibility they carry for every decision made in order to garner support for sustainable development in their nations," he said.

"Some might say there is a patronising nuance in believing Pacific nations did not know what they were doing."

A Reuters' analysis of the financial books of 11 South Pacific island nations shows China is the region's biggest bilateral lender, with loans jumping from almost zero to more than $1.3 billion outstanding in a decade.

Samoa is one of eight island nations in the South Pacific, carrying significant debt to China, but Malielegaoi said the terms were "soft" and repayments "never any problem".