Balbi confirmed that search vessels had detected a sound signal and three flares, but they were determined to have not come from the missing submarine.
He also discredited reports of a "heat spot" coming from the ocean floor.
About 30 boats and planes and 4000 people from Argentina, the US, the UK, Chile and Brazil are part of the search.
The monster multinational effort has included sonar, thermal imaging and magnetic technologies, but none has provided any trace of the vessel.
"Of those three media, in acoustic form with the sonars, infra-red with the thermal image and the detector of magnetic anomalies, there was no type of contact that is supposed to be the submarine," Balbi said, in comments translated into English.
Despite the frustrating lack of leads as investigators scour the ocean, Balbi has not given up hope.
"We're considering three scenarios: the submarine is above the surface with its engines running, adrift at sea without propulsion or submerged on the bottom of the ocean," he said.
He noted that weather was favourable for the search yesterday, but that conditions would become "complicated" today.
Argentina's Navy lost contact with its ARA San Juan submarine at 7.30am last Wednesday after it left the port of Ushuaia in the country's hostile south to sail around the tip of the Patagonia region.
The 34-year-old German-built diesel electric submarine last made contact with authorities when it was about 480km from the Argentinian coast to flag a mechanical breakdown with its batteries.