Migration a boon to both host and origin countries

In a report to the UN General Assembly, he argued that "international migration, supported by the right policies, can be highly beneficial for the development both of the countries they come from and of those where they arrive."

He however warned in his "early road map for this new era of mobility" that these benefits were contingent "on the rights of the migrants themselves being respected and upheld."

The report pointed out that migrants last year numbered 191 million, including 115 million in the developed world, compared with 155 million in 1990.

Half of all migrants around the world were reported to be women.

Europe hosted 34 percent of the world's total in 2005, North America 23 percent, Asia 28 percent, Africa nine percent, Latin America and the Caribbean three percent and Ocenia three percent as well.

Annan submitted his report ahead of a high-level meeting on international migration and development which the General Assembly will host September 14 and 15.

He announced that Peter Sutherland, the founding director general of the World Trade Organization, agreed to serve as his special representative for migration and was soliciting ideas from governments for the September meeting.

The UN chief's report was released at a time of heightened concern and social tensions in rich countries, particularly in North America and the European Union, in the face of an uncontrolled influx of illegal immigrants from poor countries.

The United States is considering sweeping immigration reform proposals, including building a huge border fence to stop the flow of illegal immigrants crossing the US border with Mexico.