"The unemployment rate among Arab youth until the age of 30 years exceeds 30 percent," the director general of the Arab Labour Organisation Ahmad Mohammed Luqman told AFP.
"Unrest and a lack of investments have boosted the number of jobless."
He said many graduates fail to find employment because their specialisations are not needed by private sector.
"Due to unrest in several Arab nations, the number of Arabs without jobs has jumped two million since 2011, making the total number of unemployed Arabs at 20 million," Luqman said on the sidelines of the annual Arab labour conference.
He told the opening session of the five-day gathering in Kuwait City that unemployment in the Arab world hit 17 percent last year, "three times higher" than the global average.
"It appears that jobless numbers will rise this year and the next," Luqman added, without providing specific figures.
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Guy Ryder, director general of the International Labour Organisation, warned that the youth unemployment problem is a threat to stability.
"Arab countries face the urgent and unavoidable task of responding to an acute crisis of unemployment," he told the conference.
"Failure to provide them with opportunities for decent work is a potent threat to the stability of our societies."
Since 2011, uprisings have swept over Tunisia, Egypt, Libya and Yemen, forcing out veteran strongmen.
Protests calling for change have also shaken Bahrain in the Gulf.
In Syria, the uprising aimed at ousting President Bashar al-Assad has become a civil war that has killed more than 220,000 people.
Arab economies are estimated to be growing at between 2-3 percent, but annual growth of around 6.0 percent must be achieved if unemployment and poverty are to be contained.