The roof of a Belconnen medical centre that caught fire on Tuesday morning could collapse, firefighters say.
Ochre Medical Centre at Kippax Shops on Hardwick Crescent caught alight.
An automatic fire alarm notified firefighters at about 8.30am, Commander Adam Garrett from ACT Fire and Rescue said.
A small amount of smoke "intensified very rapidly" when fire crews reached the scene, he said.
About 30 people were evacuated.
People at Nurture One Holt childcare centre and Kippax Veterinary Hospital were advised to stay inside because of smoke.
They are located in separate buildings.
"There has been significant structural damage and the building may remain unoccupied for weeks or months in some areas," Commander Garrett said.
"The main timber structure of the building has been compromised by the fire and there is potential [for the roof to collapse]."
Offices in the building that caught fire include TM Physio, Totally Smiles Holt and The Walking Clinic Kippax.
ACT Fire and Rescue will investigate the fire.
The Emergency Services Agency previously advised people in the area to stay inside.
"Smoke is present in the area. Individuals with respiratory conditions are advised to remain indoors and close windows," the agency said.
"Southern Cross Drive is closed in both directions between Starke Street and Florey Drive.
"The community is asked to monitor conditions and avoid the area."
