The large fire at a recycling plant on Hillside Road, Wairau Valley in Auckland has been brought under control.

Assistant Commander Barry Thomas says fire crews are now working to extinguish hot spots using ladder trucks.

The incident has been scaled down to a second alarm.

"There is significantly less smoke, but it continues to affect communities in Glenfield and Witheford Heights," he says.

"We advise people to stay inside and to keep windows closed if they smell or see smoke."

Assistant Commander Thomas says there will be at least three fire trucks monitoring the fire and working to cool the interior overnight.

" We’ll start work with heavy machinery in the morning," he says.

The cause of the fire is not known, and a fire investigation will begin at first light.

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