Alistair Darling has said that a deal to tackle climate change is "essential", as he prepared for a summit with finance ministers and bankers.
The Chancellor is hosting the G20 talks in Scotland, which bring together the most powerful economies in the world.
Speaking earlier at a dinner in Edinburgh, he said international action would lead to global recovery.
And he stressed the need for "global co-operation on a scale never seen before".
Mr Darling said: "So the G20 must push for a deal on climate financing and governance - this is an essential part of tackling climate change.
"The road ahead will be difficult, there are arguments still to be won. But that's no reason to give up, rather it's a reason to redouble our efforts."
The G20 talks in the ancient university town of St Andrews, in Fife, are the last in a series which saw leaders agree a one trillion dollar "fiscal stimulus" plan in the wake of global recession.
Mr Darling set out his ambitions at the Insurance Society of Edinburgh annual dinner before he was due to travel to St Andrews to host a formal dinner for G20 delegates and their partners. He covered measures taken at home and abroad to stabilise finances and claimed the G20 had overcome "years of painstakingly slow progress" to agree measures to see off global recession.
He added: "There can be no room for complacency amongst G20 countries this weekend. We must see through measures to support demand and repair the financial system because we cannot yet be sure the global recovery has sufficient momentum to be sustained and durable. Once we're through this, we must co-ordinate our plans for the recovery, just as we have co-ordinated our response to this crisis."
His comments came as delegates began to arrive at the Fairmont Hotel on the Fife coast. US Treasury Secretary Timothy Geithner was among the first, with delegates also visiting from countries including France, Germany, Japan and India.
