Fire crews are "winning the battle" against the SkyCity inferno that has brought central Auckland to a standstill.
But it has come at a cost, with one firefighter taken to hospital with moderate injuries after being struck by a piece of falling roof.
Fire and Emergency regional manager Ron Devlin said their strategy at containing the fire was working as planned.
"We are without any doubt winning the battle against the fire."
The roof had nearly burned out, about 20 per cent was remaining, and was being contained from spreading through the building by the water they were using.
They expected by 8pm the roof would have fully burned through and smoke begun to dissipate.
Devlin confirmed one firefighter had been taken to hospital earlier this afternoon with a concussion after being struck by a piece of the roof.
"It was unusual, may have been flicked off in the wind. It is not what we want to happen, and the reason we have been very careful with internal operations."
There were about 80 firefighters on the scene currently, down from 130 at the peak.
While the fire had affected the sixth and seventh floors, Devlin said the fifth floor looked in good shape. The roof's membrane was damaged, but structure looked to be intact.
"We expected the roof to burn and collapse in, and it is doing exactly that."
Devlin said he could not say anything about the investigation into the cause of the fire.
"My view is there is no chance of the fire spreading down. I am confident the fire is already contained.
"What we have is a burned structure, still smouldering. Probably about 20 per cent of the roof is still burning, and once that is burned it will have burned itself out."
Prime Minister Ardern told media she wanted to acknowledge firefighters who had been working under difficult circumstances.
"The team on the ground, have been incredibly professional, very focused on what they can do to preserve the building."
She also wanted to acknowledge Fletcher's and SkyCity who had been open and honest about what was happening.
Safety had been the focus. The second issue was the future of the convention centre.
She said it would take a few more days before it could be re-entered.
She said Apec 2021 would still be held in Auckland, but where it would be held was a point of discussion for Government.
"New Zealand has hosted Apec before ... without a convention centre. We had contingency in place."
When asked if world leaders would shy away from coming, she said "not at all". Leaders wouldn't base their vision on a conference room.
She said there was "no doubt" the fire had impacted on people in the city.
"It is not the city of course that we are all used to, busy, bustling, people moving between offices.
"You can see how the smoke has been debilitating for people."
She said it was "case by case" on whether workers should return to their offices in the city to work.
When asked about the economic impact on business, she indicated there would be some sort of financial compensation. It would be a small number of businesses affected.
She said there would be a hiatus for Fletcher's workers, and some would be working on the project longer than anticipated.
SkyCity chief executive Graeme Stephens said he hoped staff working on the project would be back at work on Friday.
Some workers would have a hiatus. Some left their tools on their site because of the quick evacuation.
They were working with sub-contractors and work out individual plans for their employment. There would be more jobs in the medium term.
"This devastating fire will be hugely disappointing for everyone involved ... to see this major setback, will be a blow to the workforce."
It's understood a NZDF aircraft and multiple helicopters are involved.