(ANSA) - Vatican City, November 9 - Migration is a growing issue worldwide but should be seen as an opportunity rather than a problem, Pope Benedict XVI said on Monday. Addressing the first session of the Vatican's World Congress on Migrants, the pontiff said migration was ''a bigger issue than ever before, both in terms of size and complexity''. ''It now affects nearly every country in the world and is part of the vast process of globalization,'' Benedict said. ''Many migrants leave their countries to escape living conditions that are humanly unacceptable but without finding the welcome they hope for elsewhere''. The pope urged delegates to view migration as a positive phenomenon ''that helps encourage understanding between peoples and builds peace and effective development in every nation''. The Vatican's 'migration minister' Antonio Maria Veglio' expressed similar ideas, calling for an end to ''fears arising from a view of migration as an unknown quantity and reduced solely to a public order issue to be dealt with through repressive measures''. Another key speaker at the opening session was Italian Senate Speaker Renato Schifani, part of a centre-right government whose policies have been repeatedly rapped by leading Church figures in recent months. ''Immigration risks becoming nothing more than an ideological issue if reduced to polemics between those who are concerned with security and those who worry about integration,'' said Schifani. He called for an end to immigration being used as an ''inappropriate political tool'', which he said meant ''recognizing first and foremost that security and integration, legality and welcome, and law and justice are all intertwined issues''. Veglio', who heads the Pontifical Council for the Pastoral Care of Migrants and Itinerant People, has been one of several prominent Vatican figures to express concern over the Italian government's immigration policies, particularly a new Italian law criminalizing illegal immigration.

The law imposes hefty fines on illegal immigrants as well as on Italians - with the exception of doctors and school principals - who fail to report migrants living in the country without documents.

Landlords who rent to migrants without papers face tough fines, while parents without legal status will be unable to access public services for their infants. Vatican criticism has also centred on a controversial push-back policy launched in May, under which migrant boats intercepted in the Mediterranean are sent back to Libya, which is not a party to the 1951 Refugee Convention. The 6th World Congress on the Pastoral Care of Migrants and Refugees, which runs until November 12, began with a mass in the Vatican basilica followed by an opening session and audience with the pope. Debate on the first day was dedicated to the theme of population movements in the context of globalization.

Tuesday's sessions will look at youth pastoral care among migrants and refugees, cooperation with churches of origin, and dialogue and collaboration.

On Wednesday, delegates will consider the ''needs and challenges of ecumenical and inter-religious cooperation'', while the event will close on Thursday with the presentation of a document setting out future goals.