AN RAF aircraft from Brize Norton has landed in Argentina to help search for a missing submarine with 44 sailors on board.

The Argentine navy said it lost contact with the ARA San Juan on November 15 as the submarine sailed from the extreme southern port of Ushuaia to Mar del Plata.

Since then, more than a dozen international vessels and aircraft, including those from the UK, have joined the search - with efforts hindered by stormy weather and 20ft waves.

A spokesman for the Ministry of Defence (MoD) said an RAF Voyager which took off from Brize Norton arrived in Argentina on Wednesday.

It is understood the landing of the Voyager marks the first time in as many years that an RAF aircraft which departed from the UK has landed in the South American country.

The MoD spokesman said the Voyager is packed with three tonnes of equipment, including 12 deep emergency life support pods.

HMS Protector, a Royal Navy ice patrol ship, which arrived on Sunday was deployed to the vessel's last known location, and used its sonar equipment to search below the waves for the missing sub.

An RAF C-130 has also joined the search following an offer of assistance, and members of the specialist Submarine Parachute Assistance Group are also offering expert advice.

HMS Clyde, an offshore patrol vessel, which was returning from a patrol to South Georgia has also assisted with the search efforts.

With enough food, oxygen and fuel for the crew to survive 90 days on the sea's surface, the sub only has enough oxygen to last seven days when submerged, the Argentine navy said.

A well established convention enshrined in international law means all sailors have an obligation to assist others in distress, irrespective of nationality.

The international search teams are combing the waters in a wide area of some 185,000 square miles (480,000 square kilometres), which is roughly the size of Spain.

Now missing for a week, Argentina is leading the search for their sailors, and the United States is coordinating the international response.

So far sounds detected under the sea, thought at the time to have come from the missing submarine, and seven brief satellite calls believed to have since been made by the crew, have been ruled out as coming from the lost vessel.

Pope Francis, a native of Argentina, has sent his 'fervent prayers' to the missing crew.