The National Film and Sound Archive was evacuated after smoke began filling the institution on Thursday morning.
Emergency vehicles went to the building near the campus of the Australian National University.
A humidifier in the basement overheated.
In early afternoon, the "collections management team" were preparing to go and inspect the items for smoke damage. An initial assessment was that there was no damage, either to the items or to the building itself.
The Archives were to remain closed to the public for the rest of the day.
A statement from the NFSA said: "The National Film & Sound Archive's Acton site was evacuated this morning following a mechanical incident with a dehumidifier in its basement.
"No one was hurt in the incident, which occurred at around 10am. While there was no fire, a large volume of smoke needed to be cleared.
"Emergency services are on site and the building will remain closed for the rest of the day. NFSA staff are working from home.
"The NFSA can confirm there is no damage to the building."
The archive is the nation's site for storing more than four million items, including video and audio recordings, but also significant items like costumes, scripts, props, photographs and promotional materials.
