More than 600 lobbyists from some of the world's biggest polluters have registered to the climate talks in the Egyptian resort of Sharm el-Sheikh, up 25 percent from last year, the analysis by groups including Global Witness and Corporate Accountability found.
They said that is more than the number of lobbyists from the 10 most climate-affected countries combined.
Phillip Jakpor of NGO Corporate Accountability said "There's been a lot of lip service paid to this being the so-called African COP, but how are you going to address the dire climate impacts on the continent when the fossil fuel delegation is larger than that of any African country?"
Last year at the UN climate meeting in Glasgow, they counted 503 fossil fuel lobbyists registered.
The environmental and corporate transparency groups called on the United Nations to restrict access to the talks for fossil fuel firms, which the UN chief Antonio Guterres has said are "poisoning our planet".
Oil companies have scored tens of billions of dollars in profits this year as crude prices have soared in the wake of Russia's invasion of Ukraine.
Barbados Prime Minister Mia Mottley called Monday for a 10 percent tax on oil companies to fund loss and damage.
Other small island nations threatened by the rise in seas caused by global warming joined her call on Tuesday.
"While they are profiting, the planet is burning," said the prime minister of Antigua and Barbuda, Gaston Browne, adding that company profits should go towards the creation of a "loss and damage" fund to help vulnerable countries cope with the here-and-now impacts of climate change.
The Pacific island nation of Tuvalu became this week the second country to join calls for a fossil fuel non-proliferation treaty, an initiative that seeks to stop new investments in coal, oil and gas globally and phase out production.