"Let me be blunt, too many countries are headed in the wrong direction, the virus remains public enemy number one," he told a briefing at the UN agency’s Geneva headquarters on Monday.
"If basics are not followed, the only way this pandemic is going to go - it is going to get worse and worse and worse."
He warned that the Covid-19 pandemic is worsening globally and things won't return to "the old normal" for some time.
Global infections stand at 13 million, according to a Reuters tally, with more than half a million deaths.
The WHO said that out of 230,000 new cases on Sunday, 80% were from 10 nations, and 50% from just two countries.
While numerous countries, especially in Europe and Asia, have controlled their outbreaks, Mr Ghebreyesus also hit out at world leaders for mixed messages about outbreaks that damage trust, without naming any politicians.
He called for countries to adopt a comprehensive strategy to curb soaring caseloads, noting that about half of all the new cases are now in the United States, Brazil, India and South Africa.
The US alone recorded 66,528 coronavirus cases on Saturday, a new daily record.
Global confirmed Covid-19 cases now exceed 13 million, according to Johns Hopkins University, and 570,924 people have died after contracting the disease.