Firefighters battling a giant blaze at an industrial site in Takanini say they now have the fire "under control" but are warning nearby residents to stay indoors.
The fire had earlier forced road closures, delaying rush-hour traffic.
Thick black smoke could be seen billowing from the industrial building in Inlet Rd.
Witnesses have also reported hearing several explosions.
Shortly after 6pm Fire and Emergency NZ said they had the blaze "under control".
"Crews will be remaining on site over the next few hours to dampen hot spots. People in the immediate area should stay indoors, away from smoke."
A total of 22 fire trucks battled the blaze at its peak.
But local residents only received an alert about the "major fire" from Civil Defence just before 7pm.
"Fire and Emergency currently attending major fire in Inlet Rd Takanini," the alert said.
"Residents downwind are advised to close windows and turn off air conditioning units."
Fire and Emergency New Zealand (Fenz) shift manager Peter Stevenson confirmed the United Movers building was ablaze.
He said earlier the 80m by 60m structure was fully involved and the blaze was [then] not yet under control.
"We've gone to a fifth alarm level, so that means nearly 30 appliances will be responding," he said.
Fenz received reports of the blaze at 4.26pm on Wednesday.
There were no reports of injuries and no plans to evacuate nearby buildings, he said.
The blaze was causing significant delays for rush-hour traffic in the area.
The fire is at United Movers. The business is a freight transport company with one of the largest specialised furniture body fleets in the country, its website says.
Half of the large building was in flames and the fire was spreading, a witness said.
He could see two fire trucks at the scene and plumes of smoke in the area.
"Half of Papakura is covered in smoke," he said.
A Papakura resident says she could see the smoke from her house.
"There's black smoke billowing up into the air, heading back towards Papakura.
"I can hear a popping noise and lots of sirens".
A Takanini resident said she could smell smoke from her house.
"The smoke is massive, it's not getting any smaller," she said.
A St John Ambulance spokeswoman confirmed they were at the fire in Inlet Rd assisting Fire and Emergency New Zealand (Fenz).
She said they were notified by Fenz at 4.31pm and had sent one manager and an ambulance to the blaze.
"At this stage we have no reports of injuries," she said.
A man known to the victim has been charged with assault.