More than 600 migrants rescued in the Mediterranean will be transferred from the overloaded ship that saved them onto other vessels for the voyage to Spain.

After Italy and Malta refused to accept the 629 passengers on board the Aquarius, Madrid stepped in and said it was prepared to open a port.

However, SOS Mediterranee, the NGO which operates the ship, said that the journey, in deteriorating weather conditions, would be too dangerous.

Euronews' Anelise Borges, who is the only television journalist on board the Aquarius, said that crew had been ordered to clear the decks to take on supplies and prepare to disembark passengers.

The drama began on Saturday when the ship, after receiving mayday messages came to the aid of a number of disabled small boats. Designed to carry around 500 people, it headed back towards Italy overloaded, with 11 children and four pregnant women among the passengers.

However, Italy's interior minister Matteo Salvini banned the ship from docking, saying he wanted to prevent the country becoming a "huge refugee camp". Salvini said Malta should accept the boat and its passengers, who had been rescued at sea in separate operations off the Libyan coast. When Malta also refused, new Spanish Prime Minister Pedro Sanchez made an offer to take the ship at Valencia.