"They've had to leave it," she said.
"The winds have got up and there's loose iron blowing around.
"It's a bit dangerous for them at the moment."
At its height 11 fire crews from several Gisborne brigades were needed to fight the spectacular blaze which raged for hours.
Chainsaws were used to find the source of a fire in the wall of the giant Makaraka storage shed.
Two trucks were needed before midnight to help relieve the eight crews who worked for nearly five hours to control the fierce blaze.
A fire service spokeswoman said the fire was visible, in a 20 by 30 metre storage shed.
While firefighters could see the fire, they needed the chainsaws to get inside the structure to put the flames out.
Local reporter Murray Robertson told Newstalk ZB the fire was burning through the roof of the shed.
He said there was dense black smoke pouring out.
Firefighters from all over the Gisborne District were called to tackle a blaze at the transport company on the city's outskirts.
Witnesses said smoke was pouring from the roof of the storage shed from 7pm.
Robertson said every fire truck in the district was called to help.
John Larsen owns the sawmill next door to Weatherell Transport, and said he first thought it was maize dust so he carried on working.
He said the building has been used to store crops in the past.
Larsen feared the fire would be quite fierce because the structure had been a cool store and lined with polystyrene.
