At least 15 more migrants have jumped into the sea from the Open Arms rescue ship in a desperate bid to reach shore after 19 days of being on the boat in deteriorating conditions as Italy refuses to open its ports.

Open Arms described the situation on board as “out of control” and “desperate”.

After one migrant jumped ship early in the day and was rescued by the Italian coastguard, nine more launched themselves into the sea wearing orange life vests, followed by five more.

A migrant is rescued by the Italian coastguard
A migrant is rescued by the Italian coastguard (Salvatore Allegra/AP)

All sought the southern Italian island of Lampedusa, a short distance away from the anchored ship.

A reporter with the Spanish public broadcaster TVE said the first jumper refused to return to the Open Arms and was taken to Lampedusa instead, prompting others to follow his lead.

The reporter said those jumping were “desperate and going mad” after 19 days trapped on board.

Video showed people wearing life vests floating in the sea with a coastguard vessel nearby and rubber dinghies trying to reach them.

Open Arms said the Italian coastguard rescued all 15 jumpers and took them to Lampedusa, leaving 83 migrants on board in deteriorating psychological and hygienic conditions.

A spokeswoman for the charity, Laura Lanuza, said she heard from Open Arms crew members that “those who remain aboard are threatening with jumping as well”.

The Open Arms captain previously warned Italian authorities that the crew of 17 can no longer control the situation on board as frustrated migrants resort to fighting.

The Spanish government said later it is dispatching a naval ship to Italian waters to escort the Open Arms to Spain.

The office of caretaker prime minister Pedro Sanchez said the Audaz warship will leave the southern Spanish port of Rota on Tuesday afternoon. It will arrive in Lampedusa on Friday and then sail to the main port on the island of Majorca.

Italy’s hardline interior minister Matteo Salvini has refused port access to the ship, even though six other European countries have agreed to take in the migrants, who were rescued at sea in early August off the coast of Libya.

Italian premier Giuseppe Conte announced last week that Spain, Portugal, Germany, France, Romania and Luxembourg had all offered to take the migrants.

Migrants who jumped off the Open Arms arrive on Lampedusa
Migrants who jumped off the Open Arms arrive on Lampedusa (Salvatore Allegra/AP)

While Spain has said it would open its ports to the Open Arms, the humanitarian group said the offer came too late and the voyage to Spain was too long for the migrants and the crew to face after so much time at sea.

A series of impasses with Italy started immediately after the populist coalition of League and 5-Star Movement took office last June. In the first, the Aquarius, operated by two French groups, made the long trip to Spain with 630 migrants after Madrid opened its ports.

But Spain has changed its approach, saying international marine laws and EU regulations require that rescued people need to be taken to the closest and safest port.

It also says that EU members need to find a long-term solution for dealing with migration that does not rely so much on just the Mediterranean countries.

Open Arms sailed within a few hundred metres of Lampedusa last week after winning a court ruling overturning Mr Salvini’s ban on private rescue boats entering Italy’s waters.

He has appealed against the ruling and warned that his ban on docking still holds.

Meanwhile, the Norwegian-flagged Ocean Viking, which is operated by two French humanitarian groups and has 356 rescued migrants aboard, has been sailing between Malta and the Italian island of Linosa as it waits for a port of safety to be assigned.