The scene was being handed over to Port Taranaki.
Earlier, four fire engines were sent to the scene with four specialist response vehicles, given the hazardous substance.
The spokesperson said relevant authorities had been notified, however, no extra assistance had been required so far.
Port Taranaki chief operating officer Alex Park said the fire was contained to a drum.
“Although investigations are ongoing, it is believed the drum may have been damp, which can cause the sleeves to warm and combust,” he said.
“As the sleeves contain caustic ingredients, which let off fumes when on fire, Fire and Emergency carried out decontamination of the drum.”
He said there were no injuries or any damage to port or vessel equipment.