"We've received a large number of confirmations from around the world, I think the last count was about 90 heads of state but the numbers keep coming in," said Wael Aboulmagd, special representative for the COP27 presidency, without mentioning specific countries.

"What we've decided is that our heads of state section will not be a traditional plenary-only type of affair, but rather there will be six roundtables ... for heads of state to actually engage in a discussion on the issue at hand."

Egypt is taking over the presidency of the UN climate talks from Britain, and will host the talks from Nov. 6-18 in the Egyptian Red Sea resort of Sharm El-Sheikh.

Topics for leaders' roundtables held on Nov. 7-8 would include the development of green hydrogen, water and food security, achieving a just energy transition towards renewables, and vulnerable communities, Aboulmagd said.

The themes reflect some of the Egypt's priorities as it tries to better promote the interests of developing nations and their need for financing to adapt to the impacts of climate change.

"We strongly believe that we need all the political will and momentum and direction coming from heads of state to push the process forward, because it has become a very, very adversarial process," Aboulmagd said.

Egypt is working on how to include "loss and damage" - compensation to climate-vulnerable countries already suffering from climate-related weather extremes - on the summit's formal agenda.

At last year's COP26 in Glasgow, the United States and the European Union rejected calls for a fund to compensate for such losses.

At a pre-COP meeting of heads of delegations last month, "no one seemed to say we're against an agenda item", said Aboulmagd.