The navy's new submarine fleet could reportedly cost taxpayers at least $5 billion less than expected, secret price estimates given to Defence by three international competitors show.
The confidential bids lodged by Germany, France and Japan offer a much lower cost of building an eight-submarine fleet in Adelaide than was anticipated, The Australian newspaper reported on Saturday.
The savings are in the range of $10 billion to $12 billion, when it was previously expected the project would cost about $20 billion, based on a 12-boat fleet.
Even if the government decides to build 12 submarines instead of eight, the bidders estimate the cost will reach only about $15 billion - a potential $5 billion saving.
The lower cost estimates reflect the competition between bidders to secure the deal.
The government says it will choose the winning bidder by mid-2016.