Doctors Without Borders, which has staff aboard the Aquarius, tweeted a video of some of the women aboard the ship praying on Monday morning, and said they were unaware of the diplomatic drama being waged on land over their fate.
The United Nations estimates that at least 500 people have died in 2018 trying to cross the central Mediterranean, following some 2,853 fatalities a year ago.
"This is not an inhumane act", said Transport Minister Danilo Toninelli, in charge of Italy's ports and coast guard.
Italy has long demanded that the European Union change its migration policy and make good on promises to accept more refugees, saying Italy has been left alone to coordinate rescues and accept the migrants for asylum processing.
The issue of migration to Europe and rescues at sea has become a major issue in Italy with the new government in Rome refusing to allow an NGO ship to bring rescued migrants to Italy on Sunday. Earlier in the day, the European Commission had urged action.
"We are talking about people".
"Supplies will be received shortly from an Italian vessel on to Aquarius".
Refugees International is dismayed by the Italian government's refusal to allow the SOS Mediteranée and Médecins Sans Frontières (MSF) ship, the Aquarius, to disembark in Italy.
Problems for the vessel began when Italy's Matteo Salvini, recently appointed as interior minister as part of a new right-wing government, closed the country's ports to the boat, after promising voters he would crack down on immigration.
Sanchez went on say that "It is our duty to help avoid a humanitarian catastrophe and offer a safe harbour to these people in accordance with global law".
"We are concerned at Italy authorities' directions given to Aquarius on high seas".
Italy's position, Muscat said, risks "creating a unsafe situation for all those involved".
Salvini, 45, has continued with his anti-refugee rhetoric since taking control of the interior ministry, asking on Friday for North Atlantic Treaty Organisation to defend Italy, which he says is "under attack from the south". But the new Italian government, keen to show its racism is honest, would not allow the ship to dock.
"I completely understand wanting to send Europe a signal, asking for a change in their migration policies, but this tug-of-war with Brussels can not be carried out at the expense of hundreds of men, women and children", wrote Nogarin on Facebook.
The Sea Watch still did not have any migrants on board, spokesman Ruben Neugebauer said.
Salvini has accused migrants of rape, drug-dealing and spreading diseases, and has promised to send 500,000 back to their home countries.