Reports were coming in of traffic already backed up on 15th Ave.
Northern fire communications acting shift manager Carren Larking said the service received multiple calls about the fire at 1.34pm.
''On arrival we found a well involved building fire and a second alarm for back up was made,'' she said.
Ms Larking said four fire trucks were called to the scene.
The fire is understood to have started in a ventilation system.
St Marys Catholic School, which is located nearby on 13th Ave, contacted parents to warn them on the fire. In a message, the school asked parents to avoid the area if possible when collecting their children.
A parent outside the school said there had been a "massive" amount of smoke due to the fire.
A student said they had been sent inside because smoke was coming over the school.
A police spokesperson said a person was now with police helping them with inquiries.
*Please note this fire was not at High Impact Auto Painters as first reported.