The UN's climate chief yesterday told countries at the deadlocked COP29 summit to "cut the theatrics", as pressure mounts on G20 leaders to deliver a breakthrough.

As the UN climate talks limp into a second week in Azerbaijan, the world is no closer to a finance deal for poorer countries that will determine the success or failure of COP29.

UN climate boss Simon Stiell said that "bluffing, brinkmanship and premeditated playbooks burn up precious time and run down the goodwill needed".

"Let's cut the theatrics and get down to business," he told delegates assembled in a cavernous football stadium in Azerbaijan's capital Baku.

COP29 President Mukhtar Babayev, a former oil executive turned ecology minister, urged countries to "refocus and pick up the pace".

Government ministers at the negotiating table have until Friday to break the impasse over how to raise $1 trillion a year for developing countries to cope with global warming.

With the clock ticking, pressure is mounting on G20 leaders to throw their weight behind the stalled process in Baku when they meet in Brazil for their annual summit that began yesterday.

"A successful outcome at COP29 is still within reach, but it will require leadership and compromise, namely from the G20 countries," UN Secretary-General Antonio Guterres said Sunday in Rio de Janeiro, where he is attending the G20 summit of the world's biggest economies.

"The spotlight is naturally on the G20. They account for 80 percent of global emissions," Guterres said, calling on the group to "lead by example."

In a sign that a solution could emerge from Rio, the head of the Brazilian delegation to COP29, Andre Aranha Correa do Lago, left Baku to prepare for the G20.

Besides the finance impasse, a fight is also brewing at COP29 over whether countries should recommit to last year's landmark pledge to move the world away from fossil fuels.