French authorities have launched an inquiry into the leak, reported in the Australian newspaper, and DCNS says it is waiting for the results.
But a spokeperson told the Reuters news agency that "The competition is tougher and tougher and any practises can take place in this context."
While saying that the report was "of concern", Australian Prime Minister Malcolm Turnbull pointed out that the Australian order is for 12 Shortfin Barracudas not Scorpene submarines.
The Barracudas' secret combat system is being supplied by the US.
India orders inquiry
Indian Defence Minister Manohar Parrikar ordered an inquiry to find out "what has been leaked and how much is about us".
The leaks gave the combat capabilities of the Indian fleet, according to the Australian, along with thousands of pages on the submarines' sensors and their communication and navigation system.
The Australian said DCNS implied that the leak may have come from India rather than France.
The daily, however, said the data was thought to have been removed from France in 2011 by a former French naval officer who at the time was a subcontractor for DCNS.