This amount exceeds the $9 billion allocated by the Indian government for the purchase of 126 multi-role fighters from abroad for the Indian Air Force, the paper said.

Three of the six submarines will be constructed at Mazagon Docks in Mumbai and one at Hindustan Shipyard Ltd in Visakhapatnam, with the help of a foreign contractor. The other two submarines will either be imported from abroad or constructed at a private shipyard in India, the paper said.

Under the program called Project-75 India (P-75I), apart from stealth, land-attack capability and the ability to incorporate futuristic technologies, all the six new submarines will be equipped with air-independent propulsion (AIP) systems to boost their operational capabilities, the paper said.

Conventional diesel-electric submarines have to surface every few days to get oxygen to recharge their batteries. With AIP systems, they can stay submerged for much longer periods, the paper said.

Invitations to a tender for a foreign contractor are expected to be sent to Russia's Rosoboronexport, France's DCNS/Armaris, Germany's HDW and Spain's Navantia, the paper said.

"Navy has reasons to be worried. By 2015 or so, it will be left with just half of its present fleet of 15 ageing diesel-electric submarines - 10 Russian Kilo-class, four German HDW and one Foxtrot," the paper said.