Ships and aircraft have been scrambled to search for the vessel - named Ara San Juan - in the southern Argentine Sea.
Sky News Defence Correspondent Alistair Bunkall said the British Government has offered to assist, with an A C130 Hercules stationed in the Falklands Islands on standby if required.
It has been two days since ARA San Juan provided its last location and navy spokesman Enrique Balbi said it may be suffering from a communications error.
He added: "We are investigating the reasons for the lack of communication. If there was a communication problem, the boat would have to come to the surface."