With enough shelving to stretch from Canberra to Cooma, the purpose-built repository will house around 10 million Commonwealth records when it opens in 2017.

The 18,000 square-metre facility will include a conservation laboratory, digital archives for classified and unclassified records, cold storage areas and 114 kilometres of shelving.

The last repository of its kind, National Archives director-general David Fricker said it will be a "building built for the future".

"It will be meeting the very highest environmental standards that we can for sustainability and energy consumption," Mr Fricker said.

"The target for maintaining paper records is aimed at an ambient temperature of around 20 degrees and around 50 per cent humidity so we're using as much of the architecture as possible to maintain those ideal conditions."

The facility will be built, owned, furnished, and maintained by the developer Doma Group and then leased on a 30-year basis by the National Archives.

General manager of development for the Doma Group, Gavin Edgar, said his team will draw on experience building data centres, cool rooms and laboratories in order to deliver the new archival centre.

More than 100 subcontractors - primarily from the ACT - will work on the site over the next 18 months, he said.

"The building will house Australia's most important records so it's a critical piece of infrastructure," Mr Edgar said.

"No one has done anything like this before, there hasn't been a purpose-built archive in Australia for at least 20 years."

Nor will they again, according to Mr Fricker.

"The business of the Commonwealth government now is done digitally so most of our most important records will be preserved in their digital form," Mr Fricker said.

"Across Australia the National Archives have approximately 380 shelf kilometres already in our care. Right now in the care of the state departments we have another 160 shelf kilometres which we know already exist and are coming our way to be preserved.

"We're spending every dollar we have as wisely as we can to ensure the analogue records are properly preserved going into the future but we cannot keep building more and more buildings for greater amounts of paper, it's the digital age and we have to be an archive for the future."

Mr Fricker said their focus is now to digitally preserve documents in such a way that while "technology becomes obsolete, the information is immortal".

"We will always preserve iconic records that are part of our documentary history of Australia but looking ahead to the future," Mr Fricker said.