Emergency services were called to the fire at Old Parliament House at about 11.36am on Thursday during a protest involving more than 200 people.

Mr McCormack took to social media to condemn the fire after videos were widely shared online showing flames and thick black smoke rising above the doors of the historic building.

"Old Parliament House is on fire with protesters screaming 'Let it burn! Let it burn!'. How disgraceful," Mr McCormack stated.

"An outrageous attack on our democracy, our history, our sovereignty. This modern penchant for tearing down our past serves no purpose.

"Repercussions ought to be swift and severe."

An ACT Emergency Services Agency spokesperson said upon arrival crews found the front doors of the building "well alight".

The building was evacuated as a precaution and the fire extinguished.

The cause of the fire is yet to be determined.

From December 18, First Nations people and allies have met daily at the Tent Embassy for a historical and cultural ceremony which included the deliverance of an eviction notice to the Australian Government Corporation.

Old Parliament House was used as the seat of parliament from 1927 until 1988. It is now used as the Museum of Australian Democracy.

The Aboriginal Tent Embassy sits outside Old Parliament House. The 50th anniversary of the tent embassy will happen in January next year.

Videos shared on Twitter appear to show protesters outside the building with smoke billowing out of Old Parliament House.

Ben Morton, the federal minister responsible for Old Parliament House, said the government expected illegal activity to be dealt with by police and the courts to the fullest extent possible.

"In our democracy the freedom to peaceful protest is one that we can and should celebrate," he said.

"[The] actions at Old Parliament House were not peaceful. The resulting damage undermines the message that peaceful protesters seek to deliver."

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: