Hosts Britain urged G20 finance ministers to put aside their differences and strike a deal on climate funding on Saturday despite fading hopes for an accord at key UN talks next month.
Politicians and central bankers from the world's top 20 largest and emerging economies are holding their second day of talks in the Scottish golfing town of St Andrews, aimed at bolstering the fragile world economic recovery.
In the run-up to the meeting, G20 sources said it would also address the sensitive issue of climate finance, particularly how cash committed by rich countries to help poorer nations tackle climate change should be delivered.
But a French source told AFP late on Friday that, despite the looming Copenhagen talks on cutting greenhouse gases, the issue "may not appear at all in the communique, or there could be something very vague".
This is because some emerging countries say the G20 is not the "appropriate forum" to discuss the issue, the source said.
Alistair Darling, finance minister of host country Britain, acknowledged there were "different views" around the table which would lead to "arguments" as he formally opened proceedings on Saturday.
"But I think it really is imperative that when we reach the end of the day, we have shown we've made some real progress," he added.
"If there isn't an agreement on finance, if there isn't an agreement about contributions to make sure we can deal with this problem, then the Copenhagen agreement is going to be much, much more difficult."
The UN's Copenhagen conference on December 7-18 aims to agree a successor to the Kyoto Protocol, but observers say it could at best yield a political agreement, not a fully-fledged treaty.
UN climate chief Yvo de Boer said last month that the G20 finance ministers' meeting was one of two "major opportunities" to make headway on finance before Copenhagen.
The other passed last week when European Union leaders failed to specify how much they would contribute despite agreeing that developing nations would need 100 billion euros (150 billion dollars) annually by 2020.
The overall state of the world economy will also be a key focus for the finance ministers, who will be joined in St Andrews by British Prime Minister Gordon Brown.
Now that the United States, Japan, Germany and France have emerged from recession after last year's credit crunch, the G20's focus has switched from disaster management to building a secure economic future.
Talks will touch on exit strategies from emergency measures put in place at the height of the crisis, although Darling, whose country is still in recession, has warned there is "no room for complacency".
"I hope we can agree... that we need to maintain our support for our economies until the recovery is established," he said on Saturday.
"We are still in a position where there is a lot of uncertainty, a lot of risks that need to be negotiated."
France is also expected to raise the issue of bankers' bonuses, even though agreement was reached at September's summit of G20 leaders in Pittsburgh in the US that they should be paid over a longer term and subject to repayment.
French finance minister Christine Lagarde will "question the US very directly" about how it is applying the new rules, a French source said, although it is not expected the issue will feature in the final communique.
Fresh protests organised by trade unions, religious and environmental groups are expected in St Andrews Saturday, urging the G20 to take action on climate change and jobs.
Five anti-G20 protestors blocked the road outside the plush clifftop hotel where the meeting is taking place for over an hour late on Friday.
