Italy's interior minister on Sunday called on European countries to open their ports to migrant rescue ships as he met for crisis talks with his French and German counterparts.

Italy has threatened to close its ports to charity ships that rescue migrants in the Mediterranean if other EU states do not agree to take some of the growing number of refugees onto their shores.

"We are under enormous pressure," Marco Minniti said in Paris before the talks, which are taking place ahead of an EU summit in Tallinn this week.

Italian media reports said Rome was likely to call for a European code of conduct to be drawn up for the privately-run aid boats, with the Corriere della Sera saying vessels that did not comply could be "seized".

Over the past week alone, around 10,000 migrants have been ferried to Italy after being rescued from overcrowded, rickety boats travelling from Libya.