ACT Fire and Rescue was called to the fire in Brookes Street, where three fire trucks fought the flames in a car yard and nearby building just after 10am.

A three-bay metal garage and a number of vehicles were severely damaged in the blaze, which has caused damage estimated at $50,000.

ACT Fire and Rescue Commander Greg Harmey said the yard, including the two cars inside the garage, was well alight by the time emergency services arrived.

''It was a fairly substantial fire,'' he said.

''It caused a lot of smoke, but it was quickly contained once we arrived on scene.''

The ACT Ambulance Service treated one man at the scene for minor burns to one hand before transporting him to Canberra Hospital, where he was in a stable condition.

ACT Workcover has been notified of the blaze, the cause of which is unknown at this stage.

''We believe it was accidental,'' Mr Harmey said.

''But the fire will be under investigation, as one of the workers was injured and was transported to hospital with burns to his arm.''

Emergency services received multiple emergency triple-zero calls about the fire, the first at 10.13am.

Canberrans also took to social media about the blaze in the morning.

Many people tweeted their concerns over ''another big fire'' in the northern suburb.