In a joint report, the International Labour Organization and the UN children's agency UNICEF said the number in child labour stood at 160 million at the start of 2020, an increase of 8.4 million in four years.
The ILO's annual World Employment and Social Outlook report indicated that the planet would be 75 million jobs short at the end of this year compared to if the pandemic had not occurred.
The report by the UN's World Health Organization and International Labour Organization agencies comes as the Covid-19 pandemic accelerates workplace changes that could increase the tendency to work longer hours.
Employment and Labour Minister Thulas Nxesi, trade unionists and employers' organisations from South Africa will form part of over five hundred delegates in attendance.
