Update | Dog knocking over heat lamp may have started Kirrawee storage building fire

Investigators will probe whether a dog knocking over a heat lamp caused a huge fire, which severely damaged a Kirrawee storage building last night.

The top level of the two-storey iSpace facility in The Boulevarde, on the western side of Princes Highway, was destroyed in the blaze.

However, firefighters stopped the fire reaching units on the ground level as well as adjoining buildings.

Caleb Miller, who lives nearby in Bath Road and investigated the cause of heavy smoke in the area about 8pm, said orange flames were coming from the doorways of the building when he arrived,

Mr Miller said he saw a man "running up and down the driveway".

"Someone told me he was working on a car in a unit and left a heat lamp on while he went away for a short time, and his dog, who stayed there, may have knocked it over," he said.

Mr Miller's employer rents a storage unit in the building and he said he knew valuable Ducati motorcycles and a HMV Holden Commodore were among goods stored on the top level.

Fire and Rescue NSW acting superintendent John Moore said the cause and point of origin of the fire was undetermined at this stage.

That would be a matter for investigators, who would begin their work as soon as it was safe to enter the building.

Mr Moore said he had heard reports a man and his dog had self evacuated.

There had been no injuries reported, but paramedics had assessed a woman who was affected by the smoke.

Mr Moore said, "the difficulty we have had [in extinguishing the fire] is the walls are showing signs of collapse, so we have pulled the crews out".

"We now have to tackle the fire from a defensive position and have been using three large aerial platforms to put water through the collapsed roof," he said.

"The fire has progressed from The Boulevarde side through to the rear of the building.

"It's a difficult fire, we have got a high fuel load in there with unknown contents. It could range from furniture to boats to vehicles.

"We are confident, because of the nature of construction that the units on ground level will only be smoke affected and possibly water affected. There is no fire damage that we are aware of on the ground floor.

"The firefighters have done an outstanding job in containing the fire to the building of origin.

"The premises on either side and at the rear have all been protected so there is no damage to them."

Earlier

A Kirrawee storage unit has been severely damaged by fire overnight.

Fire broke out in the two-storey iSpace facility in The Boulevarde on the western side of Princes Highway about 8pm on Friday.

No injuries have been reported.

Fire and Rescue NSW acting superintendent John Moore said the fire was still burning in the rear of the building early on Saturday.

Mr Moore said two aerial platforms were used to fight the blaze, and 12 fire trucks were on the scene initially.

"The roof has collapsed and the tilt-slab walls are in imminent danger of collapsing," he said.

"We have been able to save the units on the ground floor, but all the units on the upper levels have been destroyed."

Mr Moore said fire trucks attended from as far away as Glebe and St Andrews, but coverage for all of Sydney was maintained.

More to come