Mukhtar Babayev of Azerbaijan offered little detail about how to broker this deal but said climate finance would be a "pillar" of the COP29 summit in the petro-state in November.

"We know that the world needs to increase the overall flow of climate finance by several multiples... At COP29, we need to agree a new climate financial goal," he told ministers and diplomats at the Petersberg Climate Dialogue in Berlin.

Just a small fraction of the money needed to fund clean energy and build resilience to extreme weather in less developed countries is raised each year, eroding much-needed trust in climate negotiations.

The issue has dogged past COPs, with wealthier nations most responsible for planet-heating emissions criticised for not paying their fair share.

An earlier promise to raise $100 billion a year in climate finance was only likely met for the first time in 2022 -- two years behind schedule, according to the OECD.

But this is far from the estimated $2.4 trillion annually that developing countries -- excluding China -- will need to meet their climate and development needs.

- Short on detail -

Babayev, a former executive of Azerbaijan's national oil giant SOCAR, acknowledged the issue had been one of the thorniest in climate negotiations and "there are strong and well-founded views on all sides".

He assured they were listening to the concerns of all parties but stressed there was "no single initiative that will unlock climate finance and deliver the multiples we need".

But he did not outline a detailed timeline, financial targets, or other concrete steps that might help overcome the long-running deadlock in the months before COP29.

The push for a new pact on finance comes as nations are being urged to make deeper cuts to greenhouse gas emissions, with the world off track to meet the goals of the 2015 Paris agreement.

By early 2025, countries are to explain what steps they are taking in line with the agreement to limit global warming to 1.5 degrees Celsius above the pre-industrial level.

More money could allow for more ambitious climate action, and some developing nations want their pledges to be contingent on receiving financial aid.

India has proposed that developed countries provide $1 trillion in climate finance every year from 2025 -- 10 times the current target.

- 'The world has changed' -

But there is also a vigorous debate around who should pay, with some parties calling for China and other major emerging economies to chip in.

Under a UN climate treaty signed in 1992, only a small handful of high-income countries that dominated the global economy at the time were required to pay climate finance.

China was not among them, but today it is not only far wealthier but also the world's largest polluter.

"The world has changed, obviously, since 1992," German Foreign Minister Annalena Baerbock said Thursday.

"This is why I strongly urge those who can to join our effort, and particularly the strongest polluters of today, particularly looking also at the G20," she said.

Later she said that China, India and Saudi Arabia could be added to the list of donors.

But this expansion "risks diluting the historical responsibilities of developed nations", said Harjeet Singh from the Fossil Fuel Non-Proliferation Treaty Initiative.

"Climate finance should fundamentally aim to address and rectify past and present inequalities caused by disproportionate emissions from rich countries," he told AFP.

Babayev is expected to join G7 environment and energy ministers at a meeting in Turin, Italy, from April 28 to 30.