"If countries do not get it right then the long-term consequences could be difficulties in social integration rather than strength and integration," said Patrick Taran, senior migration specialist for the International Labour Office (ILO) at the meeting on Tuesday in the Czech capital, Prague.
He cited France's riots last year as an example.
Taran was speaking at the unveiling of a book co-written by the ILO, the International Organisation for Migration (IOM) and the Organisation for Security and Co-operation in Europe (OSCE), intended to provide migration policy guidelines for governments.
Countries sending and receiving the estimated 85 million migrant workers worldwide required better regulation, the authors said.
Host countries also have to weigh up whether their populations can accept more migrants, said Nilim Baruah, an IOM representative.
"Japan needs workers for some sectors of its economy, but it will be reluctant to have more migrants because its society is not ready nor willing for it," Taran said.
Most rich, developed, countries will draw on more migrant workers to plug skill gaps and holes in aging workforces, said Ryszard Cholewinski, IOM's labour migration specialist.
"Labour migration will have to be one of the answers to pressing issues caused by demographic change in developed countries," he added.
"Labour migration will have to be one of the answers to pressing issues caused by demographic change in developing countries"
Ryszard Cholewinski, IOM labour specialist
Developed Western economies face a 75% drop in per capita gross domestic product (GDP) from current levels by 2050 as the burden of an aging population rises, according to ILO figures, Taran said.
Russia, already home to the second largest number of migrants worldwide after the United States, also faces a 750,000 fall in its workforce this year and a six million drop by 2010, he added.
Migration is an important source of foreign earnings for some developing countries.
Remittances from migrant workers, estimated at $160 billion worldwide in 2005, are the second largest international flow of money after oil revenues, outstripping international development aid, the book stated.
Migrant workers provide a huge
source of earnings for countries
The flow of workers also represents a brain drain, especially in Africa, with skilled migrant workers often ending up performing manual work in host countries.
The book points out that women are about half of the world's international migrants.
Increasingly, they are seeking jobs on their own but still often work in domestic services and are open to exploitation, it said.