"No country can face it alone," the secretary general wrote in an opinion article in the Publico daily.
"More than ever, governments must cooperate to revitalise economies, expand public investment, promote trade and ensure that people and communities affected by the disease are supported," he said.
The virus was "infecting the global economy," he said.
The pandemic had created a "real and growing risk of a global recession," the former Portuguese premier said.
The International Monetary Fund, which releases its updated outlook on the world economy next month, has said that the severity of the slowdown will depend on how long the virus outbreak lasts and how governments respond.
In January the fund was still projecting world GDP growth of 3.3 percent, but that was before global disruptions, shutdowns and plunging oil prices.
IHS Markit, an economics research firm, this week slashed its forecast for global growth to 1.7 percent.
Coronavirus has infected close to 160,000 people worldwide and killed more than 6,000, according to the latest AFP tally of official figures.