A major fire that gutted a Mitre 10 store in Onehunga on Monday was arson, the Fire Service says.
About 70 firefighters from across the city fought the blaze that started in the Mitre 10 outdoor and camping equipment store, across the road from the main complex in Onehunga, just after 5pm on Monday.
It was initially thought an electrical fault was to blame as surrounding transformers exploded and power lines caught fire, but fire safety officers have ruled that out.
Fire Safety Officer Russell Dickson said a "matter of interest" had been uncovered at the site and police have been informed.
Mr Dickson said the store's owners are shocked and concerned at the findings.
Lack of sprinklers
The Fire Service was also investigating why the building had no sprinklers.
Mr Dickson said on Tuesday the Fire Service is continually battling to get businesses to install sprinklers, though these are sometimes not a legal requirement.
The Fire Service made similar comments after a fire at a Mitre 10 in store in the Wellington suburb of Johnsonville in 1998.
On Tuesday the Fire Service confirmed that asbestos has been found at the site.
There has also been criticism that Mitre 10 staff did not seem trained for an evacuation and did not know what to do.
Customer Julie Benjamin, who was shopping in another part of the Mitre 10 complex across the road, questions why customers were forced through the front of the building where there were flames, rather than sent to the rear to escape the blaze.
She said rather than an organised evacuation, it was everyone for themselves.
Mr Dickson said the way the people were moved out of the building will be looked into.
"If a building has more than 10 employees they must have an approved evacuation scheme which details ... what to do in the event of a fire," he said.
However, Mitre 10 management is adamant there are adequate safety procedures in its stores.
Chief executive Craig Wilson said the stores, which are run as a cooperative, meet all legal requirements. He said they work with fire consultants to ensure safety measures are in place.
"My understanding is all the staff and customers got out safely, they followed the evacuation procedure. Obviously when there's a fire there's a certain degree of panic from everybody but fortunately everybody got out."
None of the customers in the store when the fire broke out was injured.