Fire and Emergency are anticipating having the SkyCity fire under control this evening, but still expect to be on site into the weekend.
Fire and Emergency said they are confident the fire, which has been burning since about 1pm yesterday, is contained and there is no chance of it spreading.
Auckland manager Ron Devlin said they are "winning the battle", though the emergency is not over - there are still real challenges around entry to the building.
Firefighters expect the roof of the Sky City convention centre to completely burn out in two hours. They let the roof be completely destroyed so they could get better access to the fire.
Earlier today a firefighter was taken to Auckland Hospital after a piece of burning roof fell on top of them, resulting in a concussion.
Five other people have been treated for minor injuries.
As the wind picked up today, firefighters were battling the blaze in challenging conditions - gusts of up to 100km an hour were recorded in the city.
At 1pm today, with heavy rain as well as strong winds, they were still in defensive mode.
Fletcher Building said alarms on the uncompleted floors were manual and not automatic. There were automatic alarm systems on all completed floors, as well as sprinkler systems.
Dr Geoff Thomas of Victoria University's School of Architecture said one of the three most dangerous times for a building in terms of fire safety is during construction. The other two are alterations and demolition.
"The reasons these are the most dangerous times, is because that fire safety systems such as automatic fire sprinklers, automatic fire detection such as heat or smoke detection may not have been installed or are isolated (turned off) through all, or the part of the building where the building work is being carried out. Fire resistant separations between floors and to fire escape stairs may not be in place or are incomplete. At the same time hot work procedures such as cutting, grinding, welding, and torch on roofing may be taking place."
SkyCity chief executive Graeme Stephens is promising to resurrect the international convention centre project, saying it will still be an iconic destination for Auckland and the company's vision is unchanged.
He said the convention centre will be opened successfully at some point in the future.
In a press release, Auckland Civil Defence (CDEM) said Fire and Emergency are working hard to ensure that any run-off from water used to fight the fire is minimised.
"The Resource Management Act has a provision during emergency situations such as this which does allow for run-off from fire-fighting to occur. It is a balance to ensure there is minimal impact on our waterways while also ensuring that emergency services can prioritise the response.
"The water used either evaporates while trying to extinguish the fire and then is also caught in the road cesspits. This is similar to any run-off from a heavy rainstorm."
Health and safety
Those within the central Auckland area are advised to stay inside if they smell smoke and to keep the windows shut.
Civil Defense said people with pets should keep their animals indoors, especially birds which are particularly sensitive to smoke.
Auckland Regional Public Health Service said people should contact their family doctor or Healthline on 0800 611 116 if they have any difficulty breathing or develop a cough.
Auckland Mayor Phil Goff said with the thick black smoke, you could "feel the acridity in your throat, eyes and mouth, so it's unsuitable conditions for workers".
The impact on local business
The head of Auckland's city centre business association said the fire will have a significant impact on businesses in the area.
Heart of the City chief executive Viv Beck said the fire will have a knock-on effect for many businesses that rely on foot traffic, but that it is too early to quantify.
Many businesses on the normally-bustling Albert Street are closed out of concern for staff and customer safety.
It's another blow for the area, which faces ongoing delay and disruption by City Rail Link works.
Business owner Sunny Kaushal said the fire is a big set back.
"This is a very sad tragedy for the entire city in particular the CBD area. There are not many people around and the smoke smell is still quite strong," he said.
He said local businesses would assess the risks before possibly reopening tomorrow.
Ms Ardern said she has asked MSD to activate whatever forces they can to help surrounding businesses affected by the fire. Businesses that aren't able to operate is a relatively small number, she said.
Auckland District Court acting chief executive officer, Carl Crafar said due to the fire, the Auckland District Court, Chorus House and Swanson House will remain closed tomorrow.
Chorus House and Swanson House are home to other tribunals, courts, staff and services.
Some criminal cases have been transferred to the North Shore and Waitakere District Court to be heard on Thursday, 24 October.
An air quality monitor in Auckland's CBD has recorded a sharp spike in air pollution.
New Zealand hotels director at Colliers International, Dean Humphries, said there are a number of bookings already pencilled in for the centre, some of them involving up to 4000 delegates.
Jacinda Ardern said APEC will still be held in Auckland, "there's no question there".
She said the first focus was safety, the second focus was the future ability of the international convention centre.
Auckland Mayor Phil Goff is among those with concerns the centre will not be ready in time for APEC.
Auckland Tourism, Events and Economic Development chief executive Nick Hill did not rule out the centre hosting APEC, but said there were contingency plans.
The centre was the preferred venue for APEC, Mr Hill said.