The systems at one of Australia's key intelligence agencies face an increasing risk of failing because of ageing infrastructure.
Mechanical and electrical engineering services at the Australian Signals Directorate's offices in Canberra have reached the end of life and are performing inefficiently, it was revealed in parliament on Thursday.
"This has increased running costs, maintenance costs and downtime, and there is an increasing risk of the failure of the systems supporting the critical Australian Signals Directorate capability," minister Michael McCormack said.
The ASD works 24/7 to provide signals intelligence and information security to the Australian government and Defence Force.
The Department of Defence is proposing an upgrade to the infrastructure at an estimated cost of $75.4 million.
The proposed works, which have been referred to a parliamentary committee for scrutiny, will cover mechanical and hydraulic services, fire protection and control systems.
It will also involve the reconfiguration of the main foyer and upgrades to the security systems to address functionality and compliance.
"The project will deliver reliable and efficient services which are fit for purpose, compliant, and provide value for money to support the mission critical operational requirements of Australian Signals Directorate for the next 20 years," Mr McCormack said.
On Wednesday, the government told parliament the ASD was put on diesel generators during a heatwave last month amid concerns about the reliability of the energy grid.
"This meant that our agency responsible for critical infrastructure was on backup power to pre-empt a cut," said Dan Tehan, the minister responsible for cyber security.
"A lack of energy security is a direct threat to our national security."
Work is expected to begin later this year and be completed by mid-2020.
The Defence Department has also proposed a $213.4 million worth of works at Sydney's Garden Island.
It includes upgrading two existing wharfs to address "severe condition and capacity issues".
The cruiser wharf has deteriorated to the point that it is now fenced off to restrict pedestrian access and can't be used to carry out critical ship maintenance activities or berth ships except in low-wind conditions.
The proposal involves demolishing the wharfs and rebuilding them as a single wharf and extend an adjoining wharf.
"These works will enable more maintenance work to be conducted away from residential areas, reducing the noise and visual impacts," Mr McCormack said.
It's scheduled for completion by late 2020.