Gwent Police said they are now treating the fire at Broadmead Park this morning as arson and are appealing for witnesses.
A spokeswoman said nobody was injured in the fire and the property was empty at the time but that a pet dog has died.
Anyone with information should call Gwent Police on 101.
FIRE crews were called to a house fire in Broadmead Park, Newport, at around 5.30am today.
The fire was on the ground floor of a terraced house and firefighters from Maindee and Duffryn stations were on scene.
The cause of the fire is currently being investigated.