Critical records of Australian culture and history could be lost forever as the magnetic tape deteriorates beyond repair and equipment to play it back disappears, the archives has warned.

Director-general David Fricker on Tuesday announced the agency would spend the money - which is from its own internal funds - despite its budget pressures.

"After 2025 the skills and equipment needed to digitise magnetic tape will be harder to come by and the media itself will have begun to irretrievably deteriorate, so the time to act is now," he said.

The spend would grow the National Archives' digitised audiovisual collection to more than 120,000 items, taking the agency almost halfway to preserving the most critically at-risk material.

Its audiovisual records from federal agencies and public broadcasters span nearly 100 years.

Among files at risk are ASIO surveillance material, scientific research and recordings of Indigenous languages.

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National Archives assistant director of audiovisual preservation Caroline Ashworth said the $3 million would fund the first year of work under a planned five-year program to save the most critical items in the collection.

"We hold collections of great significance and importance to First Nations people across Australia, including testimonies from the Stolen Generation, Native Title land claims, royal commissions and inquiries," Ms Ashworth said.

"We also have audio and video content covering science, technology and the environment, from Antarctica to the Great Barrier Reef, Woomera to the Snowy Hydro scheme, national weather station data to Australia Post advertisements from the 1980s.

"Here at the National Archives we are doing everything we can to conserve these materials and memories for our nation and its future generations."

Earlier in 2020 it established a national panel of service providers to help it digitise at-risk recordings.

The archives has 270,000 audiovisual records on magnetic tape and has already digitised about 80,000 of the most critical items.

It's identified about 160,000 more critical, at-risk recordings in need of copying, and estimates its five-year program would need $3 million in funding each year.

Ms Ashworth said with the funding, the archives could continue momentum to digitise most of the material. Without it, the agency would attempt to grow its own internal capacity to copy the recordings.

"Unfortunately that would mean we'd be looking at doubling or tripling the amount of years it would take us to complete that task because it really is so much material," Ms Ashworth said.

"The harsh reality is as our equipment breaks down, and we can no longer find things like replacement circuit boards for broadcast quality VHS players, or we can no longer find a qualified electrical engineer who understands how to fix a VHS machine, that's when we're really going to start getting into trouble.

"We'll have this slow decline and dwindling capacity to continue to address these collections which is why we're trying to get the lion's share of it done in the next couple of years."

Ms Ashworth said preserving the archives' collection would allow future generations to interrogate Australia's history.

"There's just a wealth of knowledge contained in these audiovisual records, and we're just trying to make sure that that's going to be around forever."