A house fire in the Christchurch suburb of Redwood is being treated as suspicious.

Fire crews were called to the blaze at a two-storey residential property on Ealing Street shortly after 2am on Saturday.

Fire and Emergency Shift Manager Ryan Dawson said initial crews from Ilam and Redwood stations responded, and upon arrival, located a fire on the top floor of the house.

Two additional fire appliances from Christchurch City were dispatched to support the operation.

“Crews managed to contain the fire to the top level of the home. We departed the scene at approximately 3.30am,” Dawson said.

A fire investigator has arrived at the property on Saturday morning to determine the cause of the blaze.

No injuries were reported.

Dawson said the incident served as a timely reminder for everyone to ensure their homes are fitted with working smoke alarms.