Speaking after a working lunch with Italian premier Matteo Renzi at the World Expo in Milan, Cameron said the two countries agreed on the need for a "comprehensive" approach to a crisis which has caused a deepening rift between Italy and its EU partners.
Britain is one of the countries refusing to have anything to do with proposals to ease the strains caused by unprecedented numbers of migrants arriving by sea in Italy and Greece by distributing 40,000 refugees around Europe over the next two years.
"We need a comprehensive approach that sees a new government in Libya, that goes after the criminal gangs and where we work with you (Italy) and your intelligence fusion cell in Sicily where we will be putting in people and resources," Cameron said.
"We need a comprehensive approach to every aspect of this, particularly trying to break the link between taking people off boats in the Mediterranean and (them) getting settlement in Europe."
"We know there are different approaches in the European Union but I think we have the same values (and agree) this problem is a European problem," he said. "It is not only an Italian problem."
He added that there was "a fundamental convergence of views that this problem has to be solved at its roots, in Africa".