A leak of secret documents has no bearing on a French build of Australia's new $50 billion submarine fleet, the federal government insists.
Nevertheless, Prime Minister Malcolm Turnbull says any leak of classified information a concern.
The leaked documents, seen by The Australian, run to 22,400 pages and detail the secret combat capability of six Scorpene-class submarines French shipbuilder DCNS designed for the Indian Navy.
In April, DCNS won a hotly-contested tender over Germany and Japan to design 12 new submarines for Australia.
The Shortfin Barracuda was chosen because of its quietness, which is suited to water-based intelligence-gathering operations.
The leak raises concerns that information about the submarines, and the latest US stealth technology, might not be secure.
"The submarine that they are building for India is not submarine they are building for Australia. It is a completely different submarine," Mr Turnbull told the Seven Network on Wednesday.
Defence has told the government the reported leak had no bearing Australia's submarine program.
"The Future Submarine Program operates under stringent security requirements,," Defence Industry Minister Christopher Pyne said in a statement.
"The same requirements apply to the protection of all sensitive information and technical data for the Collins class submarines, and have operated successfully for decades."
Mr Turnbull said the leak was a reminder of the critical importance of cyber security in the modern digital world.
DCNS told News Corp "uncontrolled technical data is not possible in the Australian arrangements". It implied - but did not confirm - the leak was on the Indian side.
But The Australian said it'd been told the Scorpene data was suspected of being removed from France in 2011 by a former French Navy officer who was a DCNS subcontractor.
South Australian senator Nick Xenophon intends to pursue the the matter when parliament returns next week.
"This is really quite disastrous," he told ABC radio.
