This is the second suspicious fire in central Wellington this week.
A Fire and Emergency New Zealand spokesperson said the entire house had been consumed by the flames.
"We are treating the Wellington fire as suspicious," a police spokeswoman said.
The fire was contained to the property.
Emergency services are at the scene of the Austin St blaze. Photo / Joe Patchett
St John was called to the scene, but it was unclear if anyone was injured.
A witness said flames were bursting out of the house on to the street.
People had run around the house in an attempt to check if anyone was inside, he said. A fire investigator and police were due back at the scene this morning.
Seven Fire and Emergency New Zealand appliances and three specialist appliances responded to the fire. Photo / Joe Patchett
On Sunday night, another fire left one person in hospital and four homes damaged or destroyed in a suspicious blaze on Hanson St, Newtown.
Police are still appealing for information and CCTV footage from that fire.