“We appeal to all governments, not just European, to governments who care about people's lives so that we get a flag,” Claudia Lodesani, the head of MSF Italy, told journalists.
“We want to continue to work in the Mediterranean, the most dangerous sea in the world today, in a transparent and legal way, as we have always done,” she said.
READ ALSO: NGOs 'reeling' after Italy pressures Panama to revoke flag from Aquarius rescue ship
The Aquarius, chartered by MSF and SOS Mediterranee, is the only civilian ship still trying to rescue migrants making the perilous journey from North Africa to Europe.
It is currently carrying 58 migrants rescued in the southern Mediterranean but cannot dock after Panama on Saturday revoked its flag owing to “non-respect” of “international legal procedures”.
Malta has said it will transfer the 58 migrants to one of its boats in international waters and bring them to Malta. They will then be taken to four European countries that have agreed to take them in.
READ ALSO: Aquarius ship arrives in Malta after migrant-sharing deal
“People are still dying at sea, it isn't true that there are no more deaths, just that we see them less because there are no more witnesses, we are the last boat,” Lodesani said.
Asked whether the Vatican might give the Aquarius a flag, SOS Mediterranee operations chief Frederic Penard said such an offer would be welcome.
Vatican spokesman Greg Burke declined to comment when asked about the possibility.
Three Swiss lawmakers have meanwhile urged their country to allow the Aquarius to fly the Swiss flag.
The trio — Ada Marra, Kurt Fluri and Guillaume Barazzone, who all belong to different parties — made the demand Wednesday in parliament, citing Switzerland's “long humanitarian tradition” including migrant protection.
Marra, Fluri and Barazzone asked the government to make use of a clause in maritime law exceptionally permitting such a move and the foreign ministry confirmed to AFP that it was “competent” to do so.
“We cannot remain unmoved by the situation of all these migrants who are in danger and in distress in international waters in the Mediterranean. This concerns us all as human beings on this planet,” Barazzone told RTS radio.