South Africa's Health Minister said nation's first confirmed monkeypox patient was a 30-year-old male from Johannesburg who had no travel history, "meaning that this cannot be attributed to having been acquired outside South Africa."
Phaala said a process of contact tracing was under way.
Monkeypox is a viral disease that causes flu-like symptoms and skin lesions. It is endemic in parts of Africa, but not South Africa.
This year, as of June 15, some 2,103 laboratory-confirmed cases and one probable case of monkeypox, including one death, have been reported to the WHO from 42 countries.
"The outbreak of monkeypox continues to primarily affect men who have sex with men who have reported recent sex with new or multiple partners," the WHO said.
Some 84 percent of the cases have been found in Europe, with the most cases being reported from Britain, Spain, Germany, Portugal, Canada and France.
The World Health Organization will decide on Thursday whether to declare monkeypox a global health emergency, with a statement on the outcome likely to be issued on Friday.
WHO chief Tedros Adhanom Ghebreyesus convened the emergency meeting. on whether the outbreak constitutes a Public Health Emergency of International Concern. (PHEIC)
A PHEIC is the highest alarm that the WHO can sound, under the International Health Regulations -- the legally-binding framework agreed by 196 countries on handling public health events that could cross borders.
Besides providing a PHEIC assessment, the committee members are set to give the WHO and its member states advice on how to better prevent the spread of the disease and manage their response.
"The emergency committee will provide a recommendation to the director-general based on scientific principles, and an assessment of the risk to human health, the risk of international spread and the risk of interference with international traffic," the WHO said.
Tedros then makes the final determination on whether a PHEIC should be declared, based on their advice.
This report contains information sourced from both Reuters and Agence France-Presse