An Argentinian military submarine with 44 crew members onboard lost radio contact in November, launching a huge search-and-rescue operation off the coast of Patagonia.

A Naval spokesman reported the last known location of the vessel was 430km off the coast of Chubut, in the area of San Jorge Bay.

Rescue efforts consisting of three naval ships and two aircraft are scouring the area and attempting to make radio contact. Reports suggest that the submarine did not deploy its emergency beacon, although seven failed satellite calls were detected.

The diesel-powered 66-metre-long Class TR 1700 San Juan is one of the Argentinian navy's three submarines. The submarine was on a voyage from the southernmost city of Ushuaia to the naval base of Mar del Plata when contact was lost.