MANILA, Philippines -- There are between 30 million and 40 million irregular migrant workers worldwide who occupy the "bargain basement of globalization" but who prop up the economies of the world, the International Labor Organization (ILO) said Monday.

Manolo Abella, chief technical adviser for the ILO's Asian Program on Governance of Labor Migration, told a civil society roundtable session on the Second Global Forum on Migration and Development that the exploited condition of irregular migrant workers in host states is the result of the integration of the global markets.

"Intense competition has resulted in paper-thin margins," he said.

Irregular migrant workers, who normally enter host countries without proper documents, are vulnerable to abuse, paid wages way below those countries' standards, working more than the prescribed work hours, and usually employed in dangerous, dirty, and demeaning jobs that citizens have ignored.

But irregular migrant workers prop world economies.

Sharan Burrow, president of the International Trade Union Confederation and conference chairperson, said that if all irregular migrant workers cease their labor, "California will collapse before breakfast, London before lunch, and most of Europe just before dinner."

Burrow said of the 40 million undocumented migrant workers, 10 million are in the United States.

And with the global financial crisis, Burrow said the number is expected to increase.

"In a global financial crisis, if jobs are threatened, if regular channels of migration are constrained, then clearly we will see an increase in those desperate to make an income working without documentation in many nations," she said.

Burrow said the two-day discussions by civil society will center on expanding regular migration channels, protecting their rights and ensuring equal treatment, and the need for policy coherence which world leaders should take on.

World leaders must recognize "this challenge which is made greater by the global financial crisis and the problem of climate change. It can't wait any longer," she said.

Burrows said there is "grave fear" that the global financial crisis will result in the "impoverishment" of millions of people, citing the ILO projection that 20 million could lose their jobs because of the crisis.

"This was not expected three months ago," she said.

Of the 40 million undocumented migrant workers, an estimated 900,000 are Filipinos, according to government statistics as of December 2007.