Workers at the New Zealand International Convention Centre are demanding proof that their workplace is safe.
Those who have returned to work say there has been a strong smell of smoke and have reported experiencing dizziness, headaches, coughing and asthma flareups.
Unite Union organiser for SkyCity, Joe Carolan, told RNZ's Morning Report programme today workers had been speaking anonymously to the union.
He still hadn't seen a report from WorkSafe or from the company itself about the air conditions.
"The workers are complaining about burning eyes, burning throat and with our asthmatic workers: shortness of breath. We've had three people who've reported fainting and people have dizzy spells."
He said the union called for a health and safety strike over the weekend. While some did pull out of work, he said those who needed the money went to work.
"Unfortunately some of our workers are part-time migrant workers, they need the money. They went in and within a few hours they were reporting the same symptoms - burning eyes, sore throat and dizzy spells."
Mr Carolan was concerned about the difference of rules between corporate and cleaning staff.
"We want to know why there was a decision to rush people back to work on Thursday night when originally they'd said take the whole of Thursday off.
"We got mixed messages on Thursday night with many junior managers ordering people to come and do those shifts that they'd already planned around - with the premise that if you're pregnant or asthmatic 'don't come in'."
He said it was decided that the corporate teams at SkyCity would go back to work today.
"Why did they go back today but there's a different rule for our cleaners - mostly poor, mostly brown and migrant - they would go back to clean up for everybody, but corporate comes back today. We would've liked that everybody had those extra days to flush out the building."
RNZ has approached SkyCity for comment.
On Saturday, SkyCity said independent consultant Miller Hygiene Consultancy confirmed the air quality in its precinct is very good.
The company also said WorkSafe had examined the precinct and was satisfied SkyCity had taken appropriate actions to manage any potential health-related risks.
Roads open, business as usual
Aucklanders are being urged to take public transport, carpool, walk or cycle to help reduce congestion as the city returns to work.
While much of the cordon around the convention centre has been lifted, people heading into the central city can still expect significant delays.
All buses are back on their normal routes.
Victoria St is open as normal but Wellesley St will only be open to buses between Nelson and Hobson streets, and only two lanes will be open on both Nelson and Hobson.
The fire burned for three days last week and brought Auckland CBD to a standstill.
Auckland Mayor Phil Goff told Morning Report efforts were being scaled back.
"We're down to two fire appliances and a command unit but there are still some hotspots. The fire crews will stay there for 12 to 24 hours after the last image of any hotspots from the thermal imaging cameras indicate that that fire is extinguished."
He said a few more hotspots came to light yesterday but the fire was almost at its end and an investigation was underway.
"Hopefully we'll have a clearer picture of what the cause of the fire was and what the damage to the structural integrity of the building is. Those are the big questions.
"We're trying to discourage people from coming into that part of the city. Most of the city has been back for some time, it's business as usual."
There was still a whiff of smoke around the council building he said, but the "air quality is fine ... no danger".
"Things are now getting to the final stages."
Initially, there was eight million litres of water that had to be pumped out, Mr Goff understood that all of the water would be cleared by tomorrow.
"We've been pumping right through the weekend into the wastewater system and not into St Mary's Bay."
The convention centre was scheduled to be completed by August or September 2020, he said.
"But for SkyCity and the city as a whole, the loss of the international convention centre for maybe another year or even longer is clearly a setback."
