SkyCity, Hamilton City Council, Problem Gambling Foundation, Salvation Army, Anglican Action, Ministry of Health and Waikato DHB all spoke at the hearing.
The commission received 242 submissions, only nine of which were in support.
It was the first time an NZ casino operator had lodged an application with the Commission to substitute electronic gaming machines (EGMs) for gaming tables. It can only be approved if the commission rules that the exchange is proportionate.
It would see the number of machines increase from 339 to 399 and its gaming tables to drop from 23 to 20.
The commission had to decide whether granting the application would increase the amount of gambling opportunities and consider how harm could be minimised.
On getting the result, Hamilton city councillor Dave Macpherson praised the decision, writing on social media, "the Gambling Commission has for once ruled in favour of community to prevent increased gambling harm - about time, and a good precedent for the future.
"This cost city ratepayers up front, but saved our communities heaps in future economic and social costs."
Hamilton's Deputy Mayor Geoff Taylor wrote that he would be against fighting any appeal if pursued by SkyCity.
"SkyCity, which is a major investor in our central city, may appeal. I don't want to see our council spend ratepayers' money fighting them. I don't think it's an appropriate use of ratepayers' funds and it's not a great way to treat an important partner in our central city development."
However, Mayor Paula Southgate was not yet keen to wade into the debate about an appeal.
"I've not yet had time to read the detail. The council as a whole has not had any opportunity to discuss it, either formally or informally.
"The council doesn't yet know if SkyCity will appeal the decision, noting SkyCity has 15 days to do so. Until we have clarity on that, I'm reluctant to say much more, noting some people will be happy about the decision, and others won't."
When contacted by the Herald, SkyCity said it was still contemplating its options about any appeal.
In its application through its lawyers in court, SkyCity submitted that by reducing three of its gaming tables that would also reduce the number of players overall as the maximum number of people playing Blackjack was 21.
Data provided to the court showed that Blackjack could generate 34 games in 15 minutes with an average wager of $83.
They compared that to 2018 data which showed a gaming machine could generate an average of 151 games every 15 minutes with an average wager of $1.03.
Many of those who opposed said there would be a general increase in utilisation of the casino because of the proposal. Tables were often empty as opposed to pokie machines which most attracted most customers.
Another opposing submitter wrote: "The majority of people seeking help for their gambling issues cite electronic gaming machines as their primary problem-gambling mode. On average a gambler affects six other people."
In its raft of submissions, Hamilton City Council wrote that wager size and rate of play was not relevant as it related to the financial scale of gambling and not to the opportunity to gamble.
In response, SkyCity said that despite the potential for gambling to cause harm, the Gambling Act permitted certain types of gambling in New Zealand and made provision for proportionate changes to the gambling product mix at casinos.
The commission said the most "troubling conclusion" was the likely harm effect caused by increased utilisation in pokie machines.
"That is expressly the motivation for the present application - at busy times, [SkyCity] experiences more demand for gaming machines than it can cater for while the Blackjack tables are never fully utilised."
That left the question for the commission to increase pokie machines for that reason, which it described as "wrong".
It found that while both Blackjack and pokie machines were both "relatively harmful, it is not clear that either is inherently more harmful than the other".
However, it expected that if more machines were introduced, they would be more busy than the usually Blackjack tables would have been and therefore gambling activity overall would increase.
SkyCity has until June 19 to appeal. But whether it would remained unclear today.
When contacted, a SkyCity spokeswoman said while the organisation was "disappointed" with the decision, it was "currently reviewing it to determine if any next steps will be taken".
