The Green Party says a deal which would give SkyCity an extra 300 pokie machines is unethical and will increase the number of problem gamblers.
SkyCity boss Nigel Morrison has confirmed the deal being sought in return for financing a $350 million convention centre in Auckland.
The Greens' Denise Roche says the deal will also impact upon local businesses.
"You're looking at a loss of that money going to nearby entertainment venues – restaurants, bars, clubs that don't offer pokie machines," says Ms Roche.
"You're looking at hundreds of thousands of dollars, if not millions, being taken out of the Auckland economy to deal with the harm and mayhem caused by problem gambling."
SkyCity is threatening to walk away from the deal due to the length of time it's taking to complete.
The auditor-general is investigating the deal.
RadioLIVE / 3 News