Firefighters have battled to contain a large building fire on Auckland's North Shore.
Eighteen fire engines and other vehicles from across Auckland battled to control the blaze on Triton Drive in Rosedale, near Albany.
Both ends of Triton Dr were closed on Tuesday night while firefighters work to contain the blaze. The building is understood to house an engineering design company.
A police spokeswoman said officers assisted firefighters at the scene. There were no reports of injuries.
Keith Nelson, director of operations of Vanguard Security, said he could smell the fire and saw smoke rolling up over the buildings as he patrolled the area.
"We ran around the corner, that's when the windows blew out on the first storey and flames came out," he said.
"There were some really loud bangs and the horrible smell of something electrical burning.
"It certainly went up very fast and it was well involved very quickly."
Northern shift manager Colin Underdown said Fire and Emergency Services received multiple reports of a building fire shortly before 8.30pm.
Underdown said the fire tore through the two-storey building.
"Firefighters transmitted a second alarm just before they arrived, the building was well-involved on arrival," he said.
A fire investigator would be at the site on Wednesday, Underdown said.
Nelson said the smoke from the blaze rolling out from the building was as thick as fog.
"It was hard to breathe, especially once you got downwind of it. It was almost like a foggy night."
He said the Fenz crews were "fantastic" in their quick response to the fire, arriving at the scene as he dialled 111.