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 on Monday and Tuesday.

"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.

- Difference between life and death -

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.

Saudi Arabia has been accused of obstructing efforts to address this and other measures to reduce record-high emissions of planet-heating greenhouse gases.

The main task at COP29 is negotiating a new deal to provide developing countries enough money to cut emissions and build resilience against worsening climate shocks.

Rei Josiah Echano, disaster chief in the typhoon-hit Philippines province of Northern Samar, called for talks to be "radically fast-tracked" to help those in dire need.

Developing countries excluding China will need $1 trillion a year in outside assistance by the end of the decade, according to independent economists commissioned by the United Nations.

Stiell said it was "easy to become slightly anaesthetised" by the numbers.

"But let's never allow ourselves to forget: these figures are the difference between safety and life-wrecking disasters for billions of people," he said.

"It certainly keeps me up at night."

- Hosts criticised -

Climate-vulnerable nations want developed nations to commit at COP29 to substantially raising their existing pledge of $100 billion a year.

But donors say they cannot raise the money alone and the private sector must also be involved.

The United States and European Union also want wealthy emerging economies not obligated to pay climate finance -- most notably China -- to share the burden.

The EU is the biggest contributor to international climate finance but faces political and budget pressure, and could be left exposed should the United States refuse to pay up under Donald Trump.

The conference opened in the shadow of Trump's re-election in the United States, and efforts to shore up support for the global climate fight took another knock when Argentina's delegation withdrew from the summit.

A meeting between Chinese and European officials was seen as a glimmer of hope in an otherwise gloomy first week.

Azerbaijan lacks diplomatic experience at a time when COP observers say crucial leadership is needed to steer what some see as the most complex climate negotiations in years.

Azerbaijan's president, Ilham Aliyev, was accused of making matters harder by defending fossil fuels and attacking France over its colonial record, sparking a diplomatic incident.

Critics have questioned the suitability of Azerbaijan to host the premier climate talks.

The Council of Europe, the EU's top human rights body, called on Monday for the release of political prisoners in Azerbaijan in a letter to Aliyev.