The World Trade Organization (WTO) is close to resolving a dispute over how to spread COVID-19 vaccines more widely and fairly, but facing an "orchestrated effort" to block a deal, the body's chief said on Thursday.

WTO Director-General Ngozi Okonjo-Iweala told Reuters she had held talks this month with trade ministers from India, South Africa, the European Union and the United States on how to break an impasse over the issue of intellectual property rights.

Agreement is needed to allow some technology transfer to developing countries without manufacturers there at risk of being sued, she said.

This could help redress the gap between the vaccination rate in Africa of only 8% and 67% in developed countries that she pointed to, as well as providing vaccines that were affordable and easy to distribute.

"Ease of use, easy of distribution and affordability. These are things that could be unleashed much more if we came to these kinds of agreements," she said.

"We are getting close to an answer, a solution," she said. "On the other hand, it looks to me that there is an orchestrated effort to block success on the issue."

India and South Africa have proposed waiving intellectual property rights for COVID-19 vaccines and treatments, but developed members such as the European Union, Britain and Switzerland argue it would be better to use existing WTO rules that allow countries to award licences to local producers.

Discussions on the issue at the WTO, which takes decisions by consensus, have been deadlocked for more than a year. Okonjo-Iweala said she had brought the main actors together, with technical experts now trying to settle details.

However, the WTO head said information on delicate negotiations had since been exposed through leaks to the media, putting a "chill" on the process.

"It's not inadvertent. I think it's a deliberate means of stopping negotiations and stopping an answer. The thing is millions of lives depend on this ... Continents like Africa are waiting for this," she said.

She said it was hard to pinpoint who was responsible and did not refer to any particular report, but said they were causing mistrust.

In just one of several examples of purported details leaking out, sources in a report in trade publication Washington Trade Daily on Wednesday referred to a waiver of IP rights needing to go beyond just vaccines, as the United States has proposed, and talked of the "obdurate stance" of the European Union.

Okonjo-Iweala said all four parties to the talks had mentioned that they wanted a solution quickly and that she would continue her work towards this end. They had also agreed on a framework that could lead to a solution satisfactory to both sides.

"No one side will get 100%, but it's a satisfactory solution that I think both sides could sign onto. We are very much moving in that direction," she said.