GENEVA (Reuters) - The World Trade Organization is struggling to find an ambassador to lead negotiations on fixing its hobbled dispute system by the year-end, trade sources said, as the body's chief urged countries to keep striving for a deal.

The commitment to continue such efforts in 2024 was one of the few concrete outcomes at the WTO Abu Dhabi meeting last month which has some minor successes but failed to strike major global agreements.

The talks are aimed at agreeing reforms to the WTO's top appeals court, known as the Appellate Body, which has been idle since 2019 due to U.S. blockages of judge appointments. The lack of an Appellate Body has left dozens of trade disputes worth billions of dollars unresolved.

But days before the Abu Dhabi meeting, the talks' previous facilitator Marco Molina from Guatemala who has been widely praised for developing a new interest-based negotiating method was dismissed by his government.

The global trade watchdog had hoped to propose a replacement at its General Council meeting in Geneva on Thursday and Friday but three ambassadors declined, trade sources said.

The countries included Botswana and Honduras, they said. Their Geneva delegations did not immediately respond to a comment request.

"It's a lot of work and this is very difficult to land so it's fair enough they said no," said one WTO delegate, who is not authorised to speak publicly.

Agreements at the global body are difficult to strike since all 166 of its members must agree.

At the WTO meeting on Thursday which is the body's first major gathering since Abu Dhabi, some countries rued "abuse" of this consensus principle, referring to when just one country holds negotiations hostage by blocking a deal, sometimes in order to force progress on other topics.

However, Director-General Ngozi Okonjo-Iweala struck an upbeat tone and urged countries to keep working on talks including dispute reforms and cutting fisheries subsidies.

"We must regroup and reinvigorate how we engage in the coming weeks and months to complete the unfinished business as soon as possible," she said.