RIO DE JANEIRO: G20 leaders began arriving for a summit in Brazil on Monday to try reignite deadlocked climate talks and overcome their differences on the Middle East and Ukraine wars ahead of Donald Trump's return to the White House.

US President Joe Biden will attend his last summit of the world's leading economies, but as a lame duck leader eclipsed by Chinese President Xi Jinping, the most influential leader at this year's meeting.

Brazil's left-wing President Luiz Inacio Lula da Silva is using his hosting duties to promote issues close to his heart, including fighting hunger and climate change and taxing the super-rich.

But the wars which have bitterly divided G20 members are also set to feature prominently in the discussions.

A Brazilian foreign ministry source said Monday that some countries wanted to renegotiate a draft summit communique.

"For Brazil and other countries the text is already finalized, but some countries want to open up some points on wars and climate," he told AFP.

Biden's decision Sunday to allow Ukraine to use long-range US missiles to strike targets inside Russia – a major policy shift – could prompt European allies to also review their stance.

G20 leaders are also under pressure to try rescue UN climate talks in Azerbaijan, which have stalled on the issue of greater climate finance for developing countries.

The head of the Argentine delegation, Federico Pinedo, told AFP that Buenos Aires has raised some objections and would not "necessarily" sign the text, however. He did not elaborate.

But the Brazilian foreign ministry source on Monday downplayed the likelihood of Argentina blocking a consensus.