Fossil fuel lobbyists should be kicked out of the negotiating rooms at the international COP climate talks, global groups have urged the United Nations.

In a letter to the UN and its climate arm, which convenes the annual summit, more than 450 global campaigning organisations said any oil company representative or industry lobbyist should "not be allowed to unduly influence climate policymaking".

This allows them to "weaken and undermine the global response to climate change, and it's why we are on the brink of extinction," argue the signatories, which include Greenpeace, Oxfam, Tearfund and Friends of the Earth.

The registration of some 630 delegates with links to fossil fuel companies to attend the last such talks, COP27 in Egypt in November, sparked backlash.

Their presence explains why COP27 "refused to even formally acknowledge the role that fossil fuels play in the climate crisis," said Rachel Rose Jackson, from the campaign to Kick Big Polluters Out, which co-convened the letter.

For example, a battle to commit to phasing down all fossil fuels eventually fell by the wayside, "even though climate scenarios show there can be no fossil fuel expansion if we are to stay below critical thresholds", she said.

Campaigners have long demanded that the UN limits the access of fossil fuel executives to the inner negotiating rooms, where government representatives thrash out deals on the collective next steps towards combatting climate change.

But they escalated the demand after the United Arab Emirates' (UAE) appointed an oil company executive as president of this year's talks, COP28 in Dubai at the end of this year.

As COP28 president, Sultan al-Jaber, a government minister who also runs state the Abu Dhabi National Oil Company, is supposed to drive the direction of the negotiations, build consensus, and hold laggard governments to account.

His appointment "threatens the legitimacy and efficacy" of the conference, they said.

But the COP process is predicated on multilateralism and consensus, and gives all countries an equal seat at the table.

On Tuesday Canada's climate ambassador said it is "very important" that COP summits are "an inclusive process, that everybody has a voice".

End addiction to fossil fuels - UN chief

The campaigners accept that oil and gas majors should be involved in the discussion, as these companies will have to transform if the world is to stop burning their products.

But they should be limited to the fringes, and the UN's climate body, the UNFCCC (United Nations Framework Convention on Climate Change), should finally set up a conflict of interest and accountability process to police their involvement, the campaigners say.

They also acknowledge that boundaries between governments and industry are sometimes blurred, such as in petrostates.

Antonio Guterres, secretary general of the United Nations, has spoken increasingly critically of the fossil fuel industry, accusing them of spending more time on averting a PR disaster than a planetary one.

Responding to the appointment of Mr Al-Jaber earlier this month, Mr Guterres's spokesperson said the selection of the host COP and of the COP president is "a matter for Member States, in which the Secretary-General or the Secretariat of the UNFCCC have absolutely no involvement".

But they added that humanity is "losing the battle to prevent the worst impacts of the climate crisis," which can only be averted by "ending our addiction to fossil fuels".

The UAE COP28 team has been contacted for comment, while the UNFCCC declined to respond.

Former UK prime minister Tony Blair, who has worked for the UAE government, has backed Mr al-Jaber's appointment and the UAE's presidency.

"The UAE has shown leadership in climate investment and innovation. It is already one of the largest investors in renewables at home and abroad," he said earlier this month.

He added: "It has strong relationships with the Global North and South, East and West, and can be the honest broker needed to raise ambitions and seek real consensus."