Mumbai-based Mazagon Dock Ltd, which is building six Scorpene submarines, is likely to get a follow-on order for "some more" of these vessels.
The first Scorpene class submarine -- Kalvari, that was undocked in April -- will shortly proceed for sea trials.
It is likely to be commissioned in September next year and, thereafter, the remaining five submarines will follow every nine months as per a revised schedule.
The sources said that MDL is likely to order for more as the government does not want to waste the skill and infrastructure that has developed at the shipyard.
While the first four are conventional submarines, the last two are to be equipped with Air Independent Propulsion (AIP) system, which will enable the vessels to stay underwater for a longer duration.
Sources said that any additional submarines are likely to have AIP technology.
Scorpene submarines are being built in partnership with French firm, DCNS.
