Italy's Prime Minister Giorgia Meloni is forcing migrant rescue ships to dock further north along the country's coastline, raising fresh concerns over the process.

NGOs who operate the vessels are saying that Meloni's actions are raising their operating costs and straining their ability to continue to save lives.

Earlier this week, the Geo Barents, a vessel operated by non-governmental organization Doctors Without Borders (MSF), was told to go to the northern port of La Spezia after picking up a 69 migrants south of Malta.

MSF, which later carried out a further two rescue operations, said: "It is 100 hours of navigation from where we are at the moment."

These ships would have previously been able to dock on Lampedusa island or other Sicilian locations – a far shorter distance to travel.

But now boats are being told to go to La Spezia, the furthest and northernmost destination that Italy has assigned to an NGO ship, while Livorno in Tuscany and the eastern Adriatic ports of Ancona and Ravenna have also been used in recent weeks.

Geo Barents' head of mission, Juan Matias Gil, is less than impressed with the costs involved in the new process.

"Compared to disembarking in Sicily, going all the way to La Spezia costs us 70,000 euros ($76,240) in fuel alone," he said.

The government says the move comes to reduce the burden of hosting migrant landings in Sicily and other southern regions.

Interior Minister Matteo Piantedosi told ANSA news agency that Geo Barents was ordered to dock in La Spezia "only for a question of rotation between ports."

The new policy comes a month after a decree which forces NGO ships to request and head to a port "without delay" after each rescue, rather than continue looking for boats in distress.

Captains breaching these rules risk fines of up to 50,000 euros ($54,000) and a two-month impounding of their vessel. In cases of repeated violations, they risk permanent confiscation of the vessels.

MSF and several other charities have condemned these rules, saying they will result in more people drowning at sea.