Auckland Council has identified 209 high-rise buildings which might have the highly combustible cladding like London's Grenfell Towers which burnt down in June, up from fewer than than 100 discovered initially.
Ian McCormick, the council's building consents general manager, said the investigation into aluminium composite clad or ACP buildings in the region was almost completed.
The council has been looking into the issue for months but has now issued an update.
"To date we have identified 209 buildings that potentially have ACP panelling as part of an entire cladding system or decorative feature. We have completed the assessment of 157 of these buildings," McCormick said in the update.
In the latest update, McCormick said all buildings more than 10m tall and all hospitals were part of the ongoing investigation.
The issue is greater than initially thought.
In the winter, the council said the Auckland region had less than 100 buildings clad in ACP.
After the London Fire, Nick Smith, former Building and Construction Minister, asked the Ministry of Business, Innovation and Employment to contact all councils and check whether any high-rise buildings in in their areas had been built in ACP.
The council in Auckland was already investigating the issue after Melbourne's Docklands fire two years ago.
Sean Marshall, managing director of Takapuna-based building consultants Prendos, said there were "many examples" of buildings clad in ACP in the city.
But McCormick said ACP buildings were not necessarily dangerous and comparisons with London were not appropriate.
Auckland buildings clad in ACP had fire sprinkler systems and other measures to safeguard people, he said.
"The use of ACP in a building does not necessarily mean it is dangerous. The Grenfell tragedy reminds us how important it is to have the correct fire safety features in place. New Zealand fire safety regulations for buildings are amongst the most robust in the world and Auckland Council is confident that buildings using ACP panels in Auckland are safe," McCormick said.
The council expects the ACP investigation to be finished before the end of the year.