Some SkyCity employees working in buildings next to the fire have described the communication by managers as "appalling" and chaotic.

Workers have told Newshub that even when smoke was visible in conference rooms, and they felt sick, they were told to keep working.

"If it wasn't for social media or our friends and family that are calling us asking 'are you alright?', we would have never known something as bad as what happened was happening right next door, at our front door," says SkyCity worker Anthony Kavana, who was working a block away from the fire, at the old convention centre.

He says the stench of smoke was overwhelming, but workers were told to continue as normal.

"For them just to carry on like it's another day - that's just quite appalling."

His comments were backed up by another woman, who asked not to be identified.

If you have more information and would like to contact Michael Morrah in confidence, email MichaelMorrah@mediaworks.co.nz

She has just returned from seeing the doctor, picking up pills to help with nausea and an inhaler to help her breathe easier.

"I've just been throwing up throughout the night," she says. "I've been having continuous headaches. My eyes are burning. I can't breathe properly."

She was at the convention centre looking after 400 guests and says smoke was visible in the room.

"[I] just couldn't breathe in it....and the smoke, you could see it in front of you. That's how bad it was."

She says managers told staff to "just keep working".

She says staff put cloths over their faces but were then told that wasn't appropriate.

"Workers above us came and told us to take the cloths off because it would alarm the guests onsite."

Newshub spoke to the Institute of Finance Professionals - the group being hosted at SkyCity's convention centre yesterday.

Executive director, Jim McElwain, said while he was comfortable with communication, there was smoke in the room and some delegates left early because of it.

SkyCity says it was monitoring the air quality and shut off air conditioning units.

Its casino shut around 3pm, but workers in the VIP gaming rooms have told us they were told to stay put.

And convention centre workers say they were only told to evacuate at 5:45 pm - more than four hours after the fire started.

"To leave workers and your own clients exposed to toxic smoke for four hours shows negligence," says Joe Carolan, Unite Union organiser.

SkyCity is yet to respond to questions from Newshub about these allegations.

Newshub.