Vanuatu has lashed Australia for opposing its landmark case at the International Court of Justice, exposing the gulf in climate approaches between the region's powerhouse and island nations.
The Pacific nation has led a coalition of small states seeking a formal advisory opinion from the UN's top court, arguing high-emitting countries have a broader responsibility to reduce emissions than the Paris Agreement.
Australia is one of a number of countries which have rejected that opinion before the ICJ.
While acknowledging the graveness of the threat, describing climate change as "the greatest shared threat to all countries", Solicitor-General Stephen Donaghue said recognition of trans-boundary harm (activities by one country that affect another) did not extend to environmental harm caused by greenhouse gases.
Vanuatu climate envoy Ralph Regenvanu said those arguments amounted to "burying our heads in the sand".
"We are obviously disappointed by the statements made by the governments of Australia, the United States, Saudi Arabia, and China during the ICJ proceedings," he said.
"These nations, some of the world's largest greenhouse gas emitters, have pointed to existing treaties and commitments that have regrettably failed to motivate substantial reductions in emissions.
"These treaties are essential, but they cannot be a veil for inaction or a substitute for legal accountability.
"There needs to be an accounting for the failure to curb emissions and the climate change impacts and human rights violation that failure has generated."
Vanautu's direct criticism of Australia is rare.
Pacific governments are usually loath to rebuke Australia on any issue, both in keeping with customary practices to keep face or not cause a fuss, and to maintain relations with the region's biggest development donor.
Mr Regenvanu said the donor relationship - which includes $1.5 billion in Australian support to Vanuatu over the last 15 years - only increased the need for action.
"It is particularly concerning that some of these nations, upon whom we depend for aid and support, have not acknowledged the severity of the crisis or their responsibilities under international law," he said.
"Our dependency on their assistance makes it all the more critical for them to act responsibly and in solidarity with vulnerable nations like ours."
Climate change is a particularly sensitive topic given Australia's hopes to host the UN's annual climate talks in 2026, with bid to hold the COP31 event in the region as a partnership with the Pacific.
An Australian Government spokeswoman told AAP it "recognises the profound impact of climate change on Pacific communities, culture and livelihoods", noting it was one of more than 100 countries which supported Vanuatu to take its case to the ICJ.
"Australia was proud to join the Pacific in co-sponsoring the Vanuatu-led UN General Assembly resolution requesting an International Court of Justice (ICJ) advisory opinion in relation to the obligations of States in respect of climate change, and is actively participating in the proceedings.
"Australia is committed to working together with the Pacific to strengthen global climate action.
"It's why we're working with the Pacific on our bid to co-host COP31, ensuring their voices are elevated and further action is secured."
