Italy is violating Europe's human rights convention by pushing boatloads of migrants back to the Libyan shores where they face the risk of mistreatment, a top anti-torture watchdog said yesterday.

Last year Rome and Tripoli reached a controversial agreement that allows the Italian navy to intercept illegal migrants at sea and return them to Libya, triggering sharp criticism from the UNHCR and rights groups.

In its 2009 report on Italy, the Council of Europe's anti-torture Committee (CPT) warned the return of migrants to Libya was a breach of Rome's obligations under the European Convention on Human Rights.

The pan-European watchdog said the policy, based on its study of the period from May to July last year, violates the convention's principle that no refugee should be returned to a country where he or she is likely to face persecution or torture.

"Libya cannot be considered a safe country in terms of human rights and refugee law," it said, warning that migrants detained in Libya were "at risk of ill-treatment."

Based on the CPT's findings, "it would appear that the Italian authorities have knowingly pushed back particularly vulnerable persons, and perhaps also persons who could attest to their status as refugees," it added.

The report said all persons within Italy's jurisdiction - including at sea outside its territory - should have a chance to apply for asylum or other forms of international protection, but that none was provided to the migrants.

Human Rights Watch has also accused Italy of returning boatloads of migrants back to Libya without determining whether some might be refugees, sick or injured, pregnant women, unaccompanied children, or victims of trafficking.

Libya is a major transit nation for Africans risking their lives in rickety boats to make the Mediterranean crossing to Europe.

In 2008, some 35,000 illegal immigrants arrived on Italian shores. Of them, 75 per cent sought political or humanitarian asylum, half of whom obtained it, according to the UN refugee agency.