Firefighters have extinguished a house fire in Casey this morning.

Just after 7am, the resident of a home on Loveday Crescent was alerted by a working smoke alarm in an upstairs area and went to an investigate.

They found fire in a light fitting in the bathroom, which was beginning to spread, the resident quickly closed the door of the bathroom, evacuated all persons and called '000'.

ACT Fire and Rescue arrived a short time later to find fire spread into the roof space, with an adjoining home under threat.

The fire was quickly contained and there were no reports of serious injury.

The home has now become inhabitable, with significant fire and water damage throughout.

Loveday Crescent remained closed for most of the morning while firefighting operations were carried out.