A motorist driving past the area at the time told the Herald she saw a number of police vehicles and ambulances outside.
"I was held up at the lights and as I looked across at the ASB, I saw three cop cars.
"Then I could see two ambulances as well.''
The woman said she saw several police officers walking in and out of the building and to their cars.
A shopkeeper at the nearby Hamper Convenience Store who asked not to be named said they were unaware of what happened, and police were yet to speak to them.
The front of the ASB branch was cordoned off, and police officers were standing at the edge of the cordon.
A security officer kept pedestrians away from the scene.
Someone from Takapuna Intermediate School said: "One of the teacher's partners works at Sovereign, so we stopped the children walking down there after school."
A spokesman for Smales Farm said the incident happened inside an atrium shared by several businesses.
"The police are in attendance and we've been working with them - they've just been in the office just reviewing the tapes to try and identify what happened.
"It's really all we know at this stage, other than a gentleman seems to [have died].
"But what exactly happened, no one really knows. We're just trying to get to the bottom of it."
Asked if it appeared the man may have fallen, the spokesman said: "It appears to be that way, yes.''
Smales Farm chief executive Paul Gunn said counselling services had been made available to businesses and any of their employees who may have seen the man fall.
Worksafe was also notified, although the death is not considered a workplace incident.
"Our thoughts and sympathies are with the family and friends of the deceased at this difficult time."
The death was not related to construction work happening at Smales Farm.
