Oil executives descended on the COP29 talks in Baku for "energy day" on Friday as environmental groups denounced the presence of fossil fuel industry lobbyists at the UN climate talks.

While negotiators haggle behind closed doors on the key task of increasing climate funds for developing nations, the executives from top oil firms including France's TotalEnergies are holding events.

The "Kick the Big Polluters Out" (KBPO) coalition of NGOs analysed accreditations at the annual climate confab, calculating that more than 1,700 people linked to fossil fuel interests are in attendance.

"It's like tobacco lobbyists at a conference on lung cancer," David Tong from campaign group Oil Change International told AFP.

The presence of oil, gas and coal interests at the climate talks has long been a source of controversy.

The appointment of UAE state oil firm head Sultan Al Jaber to the presidency of last year's negotiations in Dubai was a lightning rod for criticism.

And this year's host, energy-rich Azerbaijan, launched a defence of planet-heating fossil fuels, with President Ilham Aliyev on Tuesday repeating his insistence that oil, gas and other natural resources are a "gift of God".

"It's unfortunate that the fossil fuel industry and the petrostates have seized control of the COP process to an unhealthy degree," former US vice president and leading climate activist Al Gore said Thursday.

While the Dubai summit produced a global agreement on "transitioning away" from fossil fuels, the follow-up commitment "has been very weak" and the issue "is hardly even mentioned" at COP29, he said.

"I have to think that one of the reasons for that is that the petrostates have too much control over the process," he said.

Wrangling on finance

KBPO said Japan brought employees of coal giant Sumitomo as part of its delegation, Canada included oil producers Suncor and Tourmaline and Italy brought employees of energy giants Eni and Enel.

However, some of those on the NGO list work for companies that are not primarily fossil fuel-related, including Danish offshore wind champion Orsted.

Some 53,000 people have registered to participate in COP29 in Baku, not including technical and support staff, according to the UN.

The top priority at the talks is to agree a new figure for climate finance to help developing countries adapt to climate change and transition their economies away from fossil fuels.

Rich nations are reluctant to spend much more than the $100-billion a year already committed, conscious of domestic publics angry about inflation and stuttering economies.

But developing countries warn they need at least $1 trillion to defend against the ravages of climate change and meet commitments to reach net-zero emissions.

Negotiators are struggling to wrangle a draft text into workable form before ministers arrive next week to start nailing down a deal.

Hanging over proceedings is the question of what role the United States will play on climate action and funding after Trump returns to the White House in January.

He has pledged to again withdraw from the landmark Paris agreement, raising questions about how much US negotiators can really promise and deliver in Baku.

But Gore insisted that "there is so much more momentum that even a new Trump administration is not going to be able to slow it down much," echoed the line from other Americans at the talks.

"I hope I'm right about that," he added.