Green Party co-leader Metiria Turei says SkyCity's defence of its plan to increase the number of gaming machines at its Auckland casino lacks credibility.
SkyCity and the Government are negotiating a deal that could allow the casino to have more gaming machines and tables, in return for building a $350 million convention centre.
SkyCity's chief executive Nigel Morrison says more gaming machines will not increase social harm, as most problem gambling is in underprivileged suburbs.
Ms Turei says it is true harm is caused by machines in clubs and pubs in poorer areas.
But she says casinos are where the most significant amounts of money are lost, and where people who steal money to gamble, tend to go.
The party's other co-leader, Pita Sharples, says the party recognises that New Zealanders want a convention centre, but it has to consider the potential for problem gambling too.
Labour Party leader David Shearer has also criticised SkyCity's claims that the proportion of households experiencing harm from gaming machines in casinos is 0.7% compared to 0.9% from Lotto, saying it is a distraction from its plans to install more gaming machines.
Mr Shearer says there will be a small number of problems for people playing Lotto, but it is not in the same magnitude faced by people playing the pokies.
Public OK with casino deal - Key
Prime John Key says he is comfortable with what he describes as a modest increase in the number of pokie machines at SkyCity if the deal goes ahead.
Mr Key does not believe there is strong public opposition to the Government's negotiations with SkyCity..
He says some people will be opposed to gambling, but he says that is a different debate.
Mr Key says everyone can get hung up about whether SkyCity might have a few more pokie machines, but overall, he says the number of gaming machines in New Zealand is reducing.
Mr Key says he has been upfront that he wants a convention centre built, and that he invited SkyCity to make a pitch.