ROME - Italy will not allow migrant rescue vessel Lifeline to dock in its ports, the country's interior minister confirmed on Monday.

The ship has been stranded off Malta for days with over 230 people on board. It had already been denied permit to dock by both Maltese and Italian authorities last week, after carrying out its latest rescue mission.

"The Lifeline will not be received in an Italian port," Ansa news agency quoted Italian Interior Minister and Deputy Prime Minister Matteo Salvini as saying at a press conference here.

"The vessel is illegal (in its rescue activities), and should be put under seizure," Salvini stated, adding that "I see no reason why it should dock in Italy, since it has nothing to do with our country."

The ship -- operated by German NGO Mission Lifeline -- has been waiting for a "safe harbor" in Europe since last Thursday, after rescuing 234 people in the waters between Libya and the Italian southern island of Lampedusa.

According to Salvini, the Lifeline's crew disregarded orders launched by the Italian coastguard to let the Libyan coastguard intervene and save the endangered migrants.

After the first rejection by Italy and Malta, the German NGO's ship asked France and Spain a permission to dock, but the worsening weather conditions in the central Mediterranean would currently prevent to implement such solutions, according to reports.

"It cannot be tomorrow, or after-tomorrow because of the bad weather, although we are leaving this option (sail towards France) open," Ansa quoted the NGO co-founder Axel Steier as reporting.

"Our problem is that we have 234 people on board of a 30-meter long boat, we are near a developed country, and Europe is just watching these people as they lose strength," Steier said.

The Lifeline's NGO crew was also very critical towards Italy's hard-line interior minister, and invited him to visit the rescued migrants on board.

"Dear Matteo Salvini, we have no meat on board, but humans," the NGO wrote on Facebook.

"We cordially invite you to convince yourself that it is people we have saved from drowning," the NGO wrote.

In latest weeks, Italy's new government has denied other rescue ships permit to enter Italian ports and disembark rescued migrants and refugees, in the framework of an announced crackdown on irregular immigration.

A Danish cargo ship with over 100 rescued migrants was currently off the coasts of southern Italy since Friday, waiting for a decision from the Italian authorities on whether offering them a safe harbor.

Previously, the Aquarius vessel with 629 migrants on board was turned away, forced to change its course and dock at the Spanish port of Valencia.