Other emergency services block off the section of the busy road to traffic.
The helicopter crew were returning from an unrelated mission at the time the video was taken and decided to film the extent of the blaze.
In an update shortly before 5pm, Fire and Emergency said the fire is contained but not extinguished.
A spokesperson said firefighters were now scaling back the response but operations would continue overnight.
“Crews are now able to access inside the building to continue to extinguish the fire,” said the spokesperson.
About 20 appliances were in attendance with further assistance requested. Three aerial units from Auckland were already at the scene and a fourth was on its way from Hamilton.
The firefighting will continue overnight.
A checkout operator earlier told the Herald that “smoke filled the entire store”.
The supermarket’s exterior was bubbling, blistering and peeling as firefighters tackled the blaze earlier in the day.
Many shoppers were stuck waiting for their cars parked in the supermarket’s underground carpark. All persons had been accounted for.
A supplier at the store at the time of the fire believed it started in the store room.
Three young workers said they didn’t even hear an alarm go off, it happened that quickly.
They said they saw “huge bright flames”.
Acting Inspector Ian Scoulding added: “Our advice is for the public to avoid the immediate area while emergency services are in attendance.
“We would also ask residents in the nearby area to close their windows.”
