"Four urban fire appliances attended the fire, as did a specialist vehicle from New Plymouth."
Eltham fire brigade chief fire officer David Waite says the blaze has left the house badly damaged.
"The fire was well involved when we arrived and it has left the house extensively damaged internally."
The house is not habitable in its current state, he says.
The cause of the fire is under investigation.
Jill says the fire is being treated as suspicious at this point of time.
On Thursday morning the fire service attended two blazes within a short time of each other in Eltham, just a few streets away from the location of today's blaze. Those fires are also being treated as suspicious.
A police spokesperson says an investigation is currently under way to determine if the three fires are connected.