Mukhtar Babayev, a former oil executive who now serves as Azerbaijan's ecology minister, chairs COP29 in Baku while the country's leader, Ilham Aliyev, caused a stir this week by calling fossil fuels a "gift of the God".

It comes after last year's climate talks in the oil-dependent United Arab Emirates -- presided over by the head of its state oil company -- also raised hackles among activists.

"I think it is absurd to have these petrostates that are so dependent on continuing the sale of oil and gas be the hosts of these COPs, because it's hard to miss the fact that they have a direct conflict of interest," Gore told AFP.

"The president said they're a gift from God, and I understand his sentiment, but in my opinion we should reform this process," the Nobel Peace Prize laureate said.

Azerbaijan was picked to host COP29 after Bulgaria dropped out due to Russian objections to having the conference held in a European Union country.

It was Eastern Europe's turn to host this year's Conference of the Parties.

Speaking on the sidelines of the talks in Baku, Gore said the United Nations secretary general should be able to participate in the selection process for cities and COP presidents.

The current process "meant that Russia vetoed everyone except Azerbaijan. And of course, they're a petrostate also," said Gore, who is chairman of The Climate Reality Project, a non-profit.

- Trump can't stop 'revolution' -

Gore's criticism echoed a letter Friday by a group of leading climate activists and scientists, including former UN secretary general Ban Ki-moon, who warned that the COP process was "no longer fit for purpose".

They urged smaller, more frequent meetings, strict criteria for host countries and rules to ensure companies showed clear climate commitments before being allowed to send lobbyists to the talks.

"I think that there should be a test for who is qualified to be a delegate to these COPs. Are they coming to try to find a solution or are they coming in order to block a solution?" Gore said.

Oil and gas industry representatives should be scrutinised to see if they are committed to phasing out fossil fuels, and if they are "truth tellers" or "have a record of lying about the climate crisis", he said.

His comments came as a coalition of NGOs, "Kick the Big Polluters Out", said it calculated that more than 1,700 people linked to fossil fuel interests are in attendance at COP29.

"Why should representatives of the biggest polluters in the world have more delegates than the largest national delegation, more delegates than the 10 most affected countries in the world?" Gore said.

"I think it's absurd. And I do think that the whole process needs to be reformed."

COP29 attendees are also worried about the future of US climate efforts as Trump has vowed to withdraw from the Paris agreement again.

But Gore downplayed concerns, saying his return to the White House would not "meaningfully slow" the clean energy "revolution".

"The election of Trump may slow things slightly," Gore said, but the energy transition is "unstoppable".