Investigators have confirmed the early morning fire at a Pakuranga bottle and pub store is being treated as suspicious.
The blaze, which engulfed the Lowlander Bar and Grill on Cortina Place, was attended by seven fire engines and temporarily closed off surrounding roads before rush hour.
Northern Fire Service shift manager Jaron Phillips confirmed two emergency calls were received – the earliest at 5:14am by a passerby who noticed smoke coming out of the roof.
The blaze was on the mezzanine floor, the upper level of the shop and the roof and did not spread to nearby stores.
Specialist fire investigator Linda McHugh told the Times investigators are awaiting the arrival of a crane to remove the roof before a full investigation can begin, as part of the roof is unstable and poses a safety hazard.
She said there will be no conclusive cause until investigators are able to properly inspect the building, but confirmed investigators have managed to ascertain an area of origin.
The fire is being treated as suspicious.