A United Nations special envoy has called for urgent action to address the education emergency caused by COVID-19, a UN spokesman said on Tuesday.

"In a letter sent on behalf of 280 leaders from all walks of life, Gordon Brown, the special envoy on global education, called for urgent action to address the emergency triggered by COVID-19," said Stephane Dujarric, spokesman for Secretary-General Antonio Guterres, at a regular noon briefing.

The letter, addressed to the members of the Group of 20 (G20), the World Bank, the International Monetary Fund (IMF) and others, said "there is a real danger that the health crisis will create a COVID generation who lose out on schooling and whose opportunities are permanently damaged," Dujarric said.

An immediate concern is the fate of an estimated 30 million children who, according to UNESCO, may never return to school, said the spokesman, citing the letter.

Gordon Brown and the leaders who signed the letter are calling on the G20, the IMF, the World Bank and regional development banks and all countries to recognize the scale of the crisis and to support the initiative to enable to catch-up to happen, and progress toward the implementation of the Sustainable Development Goals related to education to be resumed.

The proposed initiatives include a pledge signed by every country to protect front line education spending, an increase in international aid for education, and funding from the IMF, Dujarric noted.