Australia's new submarines will be built and brought into service using a rolling acquisition program at an initial cost of at least $56 billion.
The Defence white paper puts a figure of more than $50 billion for evaluation, design and construction of the program to replace the Collins class submarines.
A further $6 billion is set aside for weapons and systems.
The ongoing cost over the lifetime of the 12 subs could be as much as $100 billion.
A competitive process is under way to choose whether Japan, Germany or France will be involved in building the submarines, with the winner set to be announced this year.
Defence Minister Marise Payne said a rolling acquisition program would be used to deliver the submarines - the first of which will enter service in the early 2030s.
"This will ensure that, over the long-term, Australia can maintain the fleet of regionally superior boats," she said.
"A rolling acquisition program will also provide long-term planning certainty for Australian industry, for them to invest in both construction and sustainment activities."
The new submarines will require upgrades to Fleet Base West (HMAS Stirling) and Fleet Base East (Garden Island), as well as new systems for training and rescue.
As part of the program, a review will be conducted in late 2020s to consider whether the configuration of the submarines remains suitable or changes are needed.
By 2035 around half of the world's submarines are expected to be operating in the Indo-Pacific region.
Senator Payne later told reporters the $50 billion acquisition cost would be spread over time.
"You don't and can't build 12 submarines instantaneously and the costs diminish the further you get through the number of submarines," she said.
Defence force chief Mark Binskin would not provide an approximate figure for sustainment costs, "but you're talking about a fleet of 12 submarines, so it's not going to be a tiny figure".
Asked about a rule of thumb that sustainment was two-thirds the cost of a program, Air Chief Marshal Binskin said: "Let's wait and get the rigour to it."
