The Cashel Chambers building in Christchurch was gutted by a suspicious fire yesterday.
The blaze erupted just before midday on the building's third floor where some vagrants were dossing.
It quickly spread through the half-block bordered by Bedford Row and Cashel and Madras Sts.
"It's obviously a case of arson
but as to where or how [it started], it's too early to tell," said Christchurch deputy chief fire officer Greg Crawford
He said firefighters rescued one trapped woman from inside the building who was under the influence of an unknown substance and had been unable to free herself.
He believed the other people who had been dossing in the building had managed to escape.
Because of the unstable condition of the building - which was partly destroyed by a deliberately-lit fire last month - firefighters were unable to battle the blaze from the inside.
"It's too dangerous to fight this from the inside. The building is such a death-trap, there are holes cut in the floor.
"As far as we're concerned it is a very, very dangerous building.
"We've absolutely drowned it from the outside."
Firefighters had to demolish some outside walls of the building after the fire made them unstable.
The fire brought the central city to a standstill, with hundreds of people crowding the area to catch a glimpse as firefighters fought the blaze.
The streets bordering the building were cordoned off and nearby buildings evacuated.
Mike Dunlay, owner of the nearby Foam Lounge Bar, said businesses in the area had been waiting for something like today's fire to happen.
"It was only a few weeks ago, after the last fire on the property, that the owner started to take proper security measures.
"Sadly the anti-vandalism measures weren't very good ... and now a beautiful old building has near enough been destroyed."
Historic Places Trust spokeswoman Jennie Hamilton said the trust was hoping some of the historic building's facades could be saved.
"It really saddens us to see yet more of Christchurch's history go up in smoke."
- NZPA
