The United Nations agency will reconvene a meeting of the committee that will advise on declaring the outbreak a global health emergency, the WHO's highest level of alert, in the week beginning July 18 or sooner, Director-General Tedros Adhanom Ghebreyesus told a virtual news conference from Geneva.

At its previous meeting on June 27, the committee decided that the outbreak, in which cases have been rising both in the African countries where it usually spreads and globally, was not yet a health emergency.

"I continue to be concerned by the scale and spread of the virus across the world," Tedros said, adding that a lack of testing meant that there were likely many more cases going unreported.

About 80 per cent of cases are in Europe, he said.

Monkeypox, a usually mild viral infection that causes flu-like symptoms and skin lesions, has been spreading worldwide since early May.

The fatality rate in previous outbreaks in Africa of the strain currently spreading has been about 1 per cent but so far this outbreak seems to be less lethal in the non-endemic countries.

Australian Associated Press