French naval shipbuilding company DCNS has been hit by a massive data leak related to its submarines, prompting India to investigate the extent to which secrets about its Scorpene submarines have been affected.

According to a report by the Australian on Wednesday, the leak contains more than 22,000 pages with details about the secret combat capabilities of six Scorpene-class submarines that DCNS has designed for the Indian navy. Some variants of the Scorpene submarines are also used by Malaysia and Chile while Brazil is also expected to use the same vessels from 2018.

The report added that the DCNS documents — marked as “Restricted Scorpene India” — reveal ­the most sensitive combat capabilities of India’s new $3 billion submarine fleet, which can prove to be a key intelligence treasure trove for the country’s strategic rivals, such as Pakistan and China.

“I understand there has been a case of hacking,” Reuters quoted Indian Defence Minister Manohar Parrikar as saying to reporters. “We will find out what has happened.”

The six submarines are reportedly being produced at a state-run shipyard in Mumbai while the first one was expected to go into service by the end of this year.

While India is said to be investigating the leak, Uday Bhaskar, a former naval officer, told Reuters that if established, it would significantly compromise the credibility of the Scorpene submarines.

Meanwhile, DCNS said that it could not immediately authenticate the documents. However, the defense contractor didn’t rule out the possibility that the leak was part of an “economic war” waged against it by its competitors after Australia in April awarded DCNS a $38 billion contract to design and build the country’s next generation of submarines.

Although the leak has raised serious doubts about the security of DCNS' submarine project in Australia, Prime Minister Malcolm Turnbull tried to play down the impact of the leak.

“The submarine we are building or will be building with the French is called the Barracuda, quite, completely different submarine to the Scorpene they are building for India,” Agence France-Presse quoted Turnbull as saying. “We have the highest security protections on all of our defence information, whether it is in partnership with other countries or entirely within Australia.”