In March, the Australian Signals Directorate said it was at risk of shutdown unless a three-year program of upgrades was approved for its two main buildings at the Russell Defence precinct, as ageing infrastructure put counter-cyber espionage efforts, intercepts of foreign communications and military intelligence gathering in jeopardy.

Defence said the infrastructure had reached the end of its useful life and was too small for existing needs with about 1900 staff.

The foyer of one building does not meet current Defence security requirements and is congested at peak times.

ASD was forced to rely on diesel backup generators when the nation's power supply came under intense pressure last summer.

It warned the nation's cyber security was put at risk when federal departments including Defence were asked to help with load shedding during soaring temperatures on February 10.

This week the committee recommended Parliament approved the works, along with upgrades to critical infrastructure at Sydney's Garden Island, Melbourne's Immigration Transit Accommodation facility and housing for Australian Defence Force personnel at Seaward Village, Swanbourne in Western Australia.

Defence told the committee that the proposed works were 'mission critical', or 'priority one', warning that failure to upgrade would be a 'high risk' to ASD operations and have a significant impact on security.

The upgrades include a new diesel generator house, reconfigured high voltage electrical equipment, new electrical infrastructure, and an upgraded cooling, heating and air distribution system for communications and server rooms.

The entryway will be rebuilt and CCTV, access control and other security systems upgraded.

The upgrades could begin later this year and be finished by 2020.

Dan Tehan, the minister responsible for cyber security, said the upgrades would lower operating costs for ASD.

An alternative option put forward by Defence, constructing a new building, would have cost $800m.

GeoScience Australia also received the committee's support for a refresh of its main building in Symonston, costing taxpayers $17.5 million.

A refurbish and modernisation of the interior will proceed, after lease requirements for repainting and replacement of floor coverings were not followed.

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