The government has cleared the indigenous construction of seven stealth frigates and six nuclear-powered submarines to bolster naval power.

Defence sources said the decision was taken recently by the Cabinet Committee on Security.

The decision to build the six new submarines is part of the 30-year submarine building programme cleared in 1999. The plan is to have 24 submarines in 30 years. The first project was the P75, under which six Scorpene submarines are being built in India.

Another project for six more submarines was cleared by the government last year and this project was titled P75I. The Request for Proposal for the project is likely to be issued in March.

"The government has tweaked the project under which the CCS has taken a decision that the next six submarines would be nuclear-powered, unlike the conventional ones that were envisaged," sources said explaining the recent decision.

They said it was different from the P75I project and was already envisaged when the 30-year project was cleared.

The government has also decided to go ahead with the 'Project-17A' for stealth frigates under which four will be constructed at Mazagon Docks in Mumbai and three at Garden Reach Shipbuilders and Engineers in Kolkata.

Sources said this was a "follow on" order and money has been allocated for the same.