"The new contract has been put in place to deliver more efficient and effective sustainment services that will improve the availability and reliability of the Collins Submarine fleet," a statement from the Defense Materiel Organization said.
Prime contractor ASC, which built the six subs between 1990 and 2003, provides maintenance for the submarines but on a "forward-funded cost-plus" basis, the statement said.
The latest In-Service Support Contract builds on ASC's work but adds incentives for ASC to improve its efficiencies.
The deal, which starts this month, amounts to a "game-changer" for ASC, the DMO statement said.
The new ISSC is a rolling five-year contract with options to be exercised subject to satisfactory performance.
It replaces the Through Life Support Agreement signed in 2003, which "failed to deliver the required operational outcomes for navy," the DMO statement said.
By adding incentives for efficiencies the government hopes the sustainment of the Collins-class submarines can be taken off the Ministry of Defense's official Projects of Concern list, where it tops procurement projects have fallen worryingly behind schedule and increased in cost.
Australia plans to keep the Collins-class vessels in service until the 2020s.
The Ministry of Defense recently kicked off procurement for a replacement class of up to 12 submarines to be in service for around 45 years from when the first sub is commissioned in 2025.
In May, the government allocated another $700 million for maintenance for the Collins class as part of the 2012-13 defense budget.
Also in May, the government created the senior defense position general manager of submarines to focus on existing and future materiel-related submarine activities in the Department of Defense.
David Gould was appointed to the role and starts this month, reporting to Warren King, chief executive officer of the DMO.
The government also announced it has set up the Australian Military Sales Office, what it calls "a one-stop-shop for Australian defense manufacturers seeking to export their products," the DMO said.
"As a priority, it will develop a system to allow the Australian government to sell Australian made defense equipment directly to other governments on behalf of Australian manufacturers.
"It will also help Australian exporters showcase their products and capabilities at international defense exhibitions under the 'Team Australia' branding," the statement said.
The AMSO has helped the sale of classified Australian-made Counter-Improvised Explosive Device technology to the United States and will work on other projects including the sale of advanced soldier-protective equipment that has been developed for Australian troops operating in Afghanistan.
Another AMSO target is the export of Australian-built army vehicles such as the Bushmaster Protected Mobility Vehicle produced in Bendigo, state of Victoria.