ROME — A Spanish charity appealed for help on Wednesday after its ship carrying 121 migrants was turned away by Italy and Malta, and a second NGO vessel said Valletta had also refused to allow it to refuel in its waters.

Proactiva Open Arms founder Oscar Camps called on Monday for European countries to agree to take in the 121 migrants rescued last week from two boats off Libya.

"Six days have gone by without a reply, without the dignity of those on board being recognised," the non-profit organisation wrote on Twitter.

"Malta has denied the right to disembark and Italy is not answering," it said.

"We do not recognise this Europe, with its cowardly states, its empty policy... Help us."

Italy's hardline Interior Minister Matteo Salvini did reply with a ban on the Open Arms entering Italian territorial waters and a threat to seize it. "It had time to go to Spain," Salvini posted on Twitter.

"Open Arms should not forget, Italian territorial waters are closed to them and we are ready to seize the ship," Salvini said.

Italy's parliament on Monday passed further security legislation imposing stiffer penalties on NGO migrant rescue boats.

Vessels involved in search and rescue operations can be confiscated and captains fined up to one million euros ($1.1 million) for entering Italian waters without permission.

In a telephone interview with AFP, Camps urged that a similar deal be struck to that on Sunday which saw dozens of migrants from the German rescue vessel Alan Kurdi shared out between European states.

Salvini has insisted since coming to power last year that rescued migrants can land in Italy only if an agreement is already in place with other European countries to look after them.

The Open Arms currently lies in international waters southwest of Malta and east of the Italian island of Lampedusa, according to the website vesselfinder.com.

Also on Wednesday, the Ocean Viking vessel, which is jointly operated by Doctors Without Borders (MSF) and the migrant aid charity SOS Mediterranee, said Maltese authorities had denied its request to refuel in the country's territorial waters.

Nicolas Romaniuk, head of migrant rescue operations, said that the boat had originally agreed with authorities that it could refuel on open water, but permission was withdrawn two hours before the appointment.

He said no official reason was given, "but the shipping agent that takes care of us there told us by email that we could not refuel because they knew that it involved an NGO ship".

The Norwegian-flagged boat, which left on a new rescue mission from the French port city of Marseille on Sunday, has enough fuel to last up to 12 days, he said. — AFP