Firefighters are working to solve the cause of an Ascot Park house fire that has caused the roof to collapse

20 firefighters were called to the dramatic scene- but not before an off duty firefighter had arrived at the scene and rescued a dog trapped inside the house.

20 firefighters rushed to a dramatic scene in Ascot Park, where a house roof collapsed during a fierce blaze - but not before an off duty firefighter had arrived at the scene and rescued a dog trapped inside the house.

Residents in the neighbourhood called emergency services after noticing billowing thick black smoke at 12:40pm on Saturday, July 19.

7NEWS reported that an off-duty firefighter rescued a pet dog trapped inside the ferocious house fire before crews arrived just before 1pm.

A MFS spokesperson said that the fire has been contained shortly after the crews arrived.

House fire Ascot Park Picture: Supplied

“It occurred at a single story home. The building itself has suffered significant structural damage - we are talking roof collapse” they said.

“Firefighters are still on scene. It was contained, but hotspots are still being put out and the roof collapse is making that more difficult.”

Investigators are on the way to determine the cause of the fire and hope to reach a conclusion later this afternoon.

Originally published as Firefighters are working to solve the cause of an Ascot Park house fire that has caused the roof to collapse