Tedros also told an online media briefing he was “especially worried” about the outbreak in Central and South America, where infections have been spreading rapidly.
The drug forms part of the World Health Organisation’s (WHO) solidarity trial, an international clinical trial to help find an effective treatment for the virus.
WHO director general Tedros Ghebreyesus lauded South Africa for its handling of the lockdown.
Leading Italian doctor Alberto Zangrillo sparked a furore on Monday with claims that COVID-19 had lost some of its potency.
US President Donald Trump said Friday he was severing US ties with the WHO, which he says failed to do enough to combat the initial spread of the novel coronavirus.
Health Minister Zweli Mkhize said that the Western Cape now had two-thirds of all COVID-19 cases in the country.
US President Donald Trump and others have pushed hydroxychloroquine as a possible coronavirus treatment, but the WHO on Monday called time in its multi-country trial, called Solidarity.
The WHO told AFP that it was in close contact with Dutch researchers investigating three cases where the virus appears to have been passed to humans from minks.
Hydroxycholoroquine has been touted by Donald Trump and others as a possible treatment for the disease caused by the novel coronavirus.
“My first point for Africa, my first concern, is that a lack of testing is leading to a silent epidemic in Africa. So we must continue to push leaders to prioritize testing,” special envoy Samba Sow told a news conference.
Chinese Foreign Minister Wang Yi said Washington had been infected by a 'political virus' to continually attack China.
More than 5.27 million people were reported to have been infected globally with the virus and 339,267 have died, according to a Reuters tally.
Unlike in Europe and the United States, where the elderly were hardest-hit, a significant number of deaths in Brazil have been younger people, who are often driven by poverty to work despite the threat of infection.
While many hard-hit European countries have significantly curbed the contagion, Latin America is becoming a new hotspot with cases on the rise.
The global health body said 106,000 new cases of infections of the novel coronavirus had been recorded in the past 24 hours, the most in a single day since the outbreak began.
WHO Director-General Tedros Adhanom Ghebreyesus defended the agency’s role after the United States again withheld full support for a resolution on the pandemic.
US President Donald Trump has been locked in a bitter spat with Beijing, alleging it covered up the initial COVID-19 outbreak in central China late last year before the disease unleashed death and economic devastation across the planet.
Speaking by video-link, a wide range of country leaders and health ministers hailed the WHO's efforts to coordinate the response, and urged more funding and stronger support for the UN agency.
