The coronavirus pandemic has heaped pressure on the troubled World Trade Organization, a WTO leadership candidate said, warning the crisis could spell the end of rules-based international trade altogether.

Liam Fox, Britain's first post-Brexit international trade secretary and one of eight candidates vying to become the WTO's next director-general, voiced concern that countries might turn their backs on its multilateral trading model.

"The reaction of some countries to the Covid emergency will be to seek solace in protectionism and to believe that they will get more resilience by ... closing themselves off, if you like, from the global economy," he told AFP Thursday in an interview.

"Exactly the opposite I believe is true," he said during a conversation using the video link Zoom, insisting that countries will find more security by opening up and ensuring diversity of supply.

"For the rules-based trading system, Covid could be the kiss of life if we embrace the right policies -- or the kiss of death if we don't."

Roberto Azevedo stepped down as the WTO chief this week, a year ahead of schedule. His successor will lead an institution that was already facing multiple crises before the pandemic hit.

The Geneva-based organisation is mired in stalled trade talks and struggling to curb trade tensions between the United States and China.

The global trade body has also faced relentless attacks from Washington, which has crippled the WTO dispute settlement appeal system and threatened to leave the organisation altogether.

And now the WTO, set to remain leaderless for several more months at least, is struggling to help members navigate a severe global economic slump sparked by the coronavirus pandemic.

The WTO has presented a timeline for selecting one of the eight leadership candidates -- three Africans, two Europeans, two from Asia and one Latin American -- within a few months.

Fox acknowledged "there is at least a technical chance that that could be slowed down" by the politicised climate.

But he said WTO members were eager to settle quickly on a new director-general to help navigate an increasingly complex reality.

"All the issues faced by the new DG are super-charged by the Covid crisis," he said. "I think there is an understanding of the urgency in the process."

Fox, 58, said that as a politician with long experience of elections, he found the WTO selection process "highly unusual".

It includes elimination rounds during which countries express their preferences in confidential "confessionals".

"I would describe it as somewhere between choosing a pope and the Eurovision Song Contest," he quipped.

Fox insisted he was the right person to tackle the numerous political issues facing the WTO, and that he could help bring Washington back into the fold and rescue the WTO's appeals system.

The Brexit-backer rejected suggestions his chances might be hurt by animosity towards Britain over its decision to leave the European Union.

Most countries, including European nations, see challenges facing global trade as going "way beyond the issues of Brexit," the Scot said.

"These are very big and important issues... and made more important by the Covid emergency," said Fox.

"If we get them wrong, it would make anything that might happen with Brexit look like a picnic."