Italy's populist government has approved stiff fines for migrant rescue boats that defy orders to stay out of Italian waters.

Interior Minister Matteo Salvini said Tuesday after a Cabinet meeting that a new decree allows fines of up to 50,000 euros ($57,000) when charity boats carrying migrants who were rescued at sea enter Italy's ports without authorization.

The regulation also permits undercover police investigations of possible migrant trafficking operations and facilitates electronic eavesdropping on suspected people smugglers.

Since becoming interior minister a year ago, the right-wing Salvini has further toughened Italy's oversight of rescue boats operated by private aid groups.

The number of smuggler vessels embarking from Libya and the corresponding number of migrant arrivals have dwindled.