Italy is to continue its policy of towing migrant boats back to the coast of Libya.
The United Nations refugee agency has complained to Interior Minister Roberto Maroni to complain about the practice of deporting migrants intercepted at sea.
The agency says this is against the 1951 Geneva Convention.
Hundreds of people have been deported in recent weeks.
Meanwhile, the Italian government has given Libya three patrol boats to help aimed at combat the flow of illegal migrants.
An additional three boats will be handed over in the coming weeks. They will take part in joint patrols with the Italian navy from Friday.
An agreement between Tripoli and Rome to maintain joint naval patrols in the Mediterranean was signed earlier this month and comes into force on Friday.
Libya has been a major staging post for migrants from Egypt and sub-Saharan Africa wanting to reach Europe.
Nearly 37,000 immigrants landed on Italian shores last year.
On Thursday, the Italian government passed a law which would impose fines of up to 10,000 euros ($US13,000) on illegal immigrants and jail for up to three years for people who let them accommodation.