“a threat to everybody in the world” and would trigger a recession “that probably has no parallel in the recent past”.
The global spread of the disease also risks “enhanced instability, enhanced unrest, and enhanced conflict,” he added during the launch of a UN report on the socioeconomic impacts of the virus.
The report describes the pandemic as “a global health crisis unlike any in the 75-year history of the United Nations, one that is killing people, spreading human suffering, and upending people’s lives”.
It adds: “But this is much more than a health crisis. It is a human crisis. The coronavirus disease is attacking societies at their core.”
Mr Guterres called for a stronger and more united international response to tackling the crisis, an “unprecedented test” which he said had left societies “in turmoil” and economies “in a nose-dive”.
That will only be possible “if everybody comes together and if we forget political games and understand that it is humankind that is at stake,” he stressed.
The secretary-general said many countries had been ignoring World Health Organisation (WHO) guidelines on tackling the disease and choosing to go their “own way”.
“Large-scale, coordinated and comprehensive” action is needed “in which all countries join the same efforts in order to commonly suppress the transmission,” he added.
He said the response must be one that “scales up health capacity for testing, tracing, quarantine and treatment, while keeping first responders safe, combined with measures to restrict movement and contact”.
The UK has been criticised by a former WHO director for failing to conduct widespread coronavirus testing, while concerns have been raised about countries such as Sweden opting not to implement strict social distancing measures.
Mr Guterres’ comments came in a live-streamed press briefing held shortly before the number of confirmed coronavirus cases worldwide topped 860,000. More than 42,000 people infected have died.
The vast majority of those deaths have been wealthy countries in the northern hemisphere, with more than half of them in Italy, Spain, China and France.
But Mr Guterres warned Covid-19 could kill millions of people as it spreads to developing nations in the south, adding he was “particularly concerned with the African continent”, where many nations have fragile health systems.
He said it was “essential that developed countries immediately assist those less developed to bolster their health systems and their response capacity to stop transmission”.
“Otherwise we face the nightmare of the disease spreading like wildfire in the global south with millions of deaths and the prospect of the disease re-emerging where it was previously suppressed,” he added.
G20 leaders last week pledged to inject more than £4 trillion into the global economy to limit job and income losses, but Mr Guterres said most of this money was mobilised “by the developed world to support their own economies”.
He warned: “We are far from having a global package to help the developing world to create the conditions both to suppress the disease and to address the dramatic consequences in their populations, in the people that lost their jobs, the small companies that are operating and risk disappearing, those that live with the informal economy that now have no chance to survive.
“Massive support to the developing world is still required.”
The UN has announced the establishment of a Covid-19 Response and Recovery Fund to support efforts in low and middle-income countries, with the aim of swiftly enabling governments to tackle the crisis and promote recovery.
The secretary-general expressed hope there would be “a positive response” from the international community to help vulnerable people including the tens of millions of refugees and internally displaced people, those in the slums of big cities in the global south, and poor people in middle-income countries who are more numerous than in the least developed countries.