Fire damage to the front doors of the historic Old Parliament House in the nation's capital, Canberra, was "tragic" and potentially irreparable, Museum of Australian Democracy Director Daryl Karp says.
The fire broke out amid a protest at the entrance to the historic building on Thursday, causing extensive damage to the doors and portico.
"We have a team of conservators standing by to come in and have a look and see what can be done because we are a museum, we love to be open 364 days of the year," Karp told the ABC.
"To actually be closed and to be closed because of violent protests is really tragic."
Protesters had been outside the building for more than a week and started a traditional smoking ceremony, which may be connected to the fire that engulfed the front entrance of the historic building.
A previous fire was started by protesters near the building on Dec. 21.
Karp said further examination was needed to determine if damaged parts of the heritage-listed building could be fixed.
She said the doors were "pretty damaged" and the portico had been "really burnt out."
"The portico was built specifically for the Queen's visit in the 50s and so it has substantial significance, as do the doors which are from 1927," she said.
"It's unclear whether we can restore the doors or not. Obviously they are pretty significant collection items and that's a really big one for us."
Karp said the lower gallery floors were original 1927 lino.
"It's got a lot of soot and a lot of water on it so we will need to check it is still okay.
"It's still a police crime scene and we are not able to go through it."
Social media footage shows police dragging protesters away from the front steps of the building and a large fire burning at the doors.
Aboriginal Tent Embassy activists distanced themselves from the protest, saying a smoking ceremony that took place did not have the knowledge or consent from the Embassy Council.
ACT Policing announced on Thursday it would launch an investigation into the blaze, noting while there were no injuries but there was "extensive water damage" to the building's interior.
Old Parliament House will remain closed while the investigation is undertaken.