Fire engulfed nearly 5000 sq m of plastic and six shipping containers at a recycling facility storage area in Waiuku Business Park on Monday.
The fire spread to six containers at an adjacent business, Designmax Homes.
Fire and Emergency NZ said the latest blaze was believed to be a flare-up of Monday's.
Waiuku Business Park's owner Sam Wulff said today the containers were on land not part of the business park and he had not been contacted by police about the fire overnight.
A Designmax Homes staff member said the business did not want to comment.
Meanwhile, a man has been charged over Monday night's fire.
Police say a 30-year-old local man is facing an arson charge and was due to appear at Pukekohe District Court today.
"They found two shipping containers [on fire], that were involved in the fire the other night."
The fire was out by about 5am, he said.
Crews did not call a fire investigator or police, but the investigation into Monday night's fire was ongoing, he said.
Wulff earlier told RNZ he had leased out part of the industrial lot to plastics recycling company Future Post.
He was shocked to learn that the fire might have been deliberately lit there and said the recycling facility converted waste plastic into fence posts.
