A surge in the number of problem gamblers identified by SkyCity has not been matched with preventive actions such as exclusions from the casino.
Reports prepared for the Gambling Commission by SkyCity show the number of customers with signs of problem gambling rose from 661 in 2008 to 2582 last year.
But while the casino identified 291 per cent more people with gambling problems, exclusions from the casino over the same time period went up by 27 per cent.
In 2008, 428 people were excluded from the casino, compared to 544 last year.
Graeme Ramsey from the Problem Gambling Foundation said the figures, released under the Official Information Act, showed SkyCity was better at identifying problem gambling.
"But my major concern is that while they are getting better at identifying it, that is not being met by a corresponding improvement in how they're dealing with problem gambling."
Mr Ramsey said he would expect a near 300 per cent increase in identifying signs of problem gambling would be matched by casino exclusions, staff interventions and other measures.
"But they're clearly not ... it's my belief that actually the business model is dependent upon people with problems.
"There's an inbuilt dilemma for SkyCity in terms of dealing with them and maintaining returns to shareholders."
Grainne Troute, SkyCity's general manager group services, said the increase reflected more effective monitoring by the casino, which was acknowledged by the Gambling Commission.
"This monitoring results in a range of different outcomes that are not limited solely to exclusion.
"It is important to point that our host responsibility for SkyCity covers not just gaming but also responsible service of alcohol."
The figures come amid negotiations between the Government and SkyCity over a $350 million national convention centre.
SkyCity has offered to build the centre in return for concessions on gambling.
It wants early renewal of its licence, more gambling machines, automated gaming tables and an increase in the number of other table games.
SkyCity's licence requires it to report to the Gambling Commission every six months on its implementation of its Host Responsibility Programme.
The casino licence granted to the company required the commission to review the programme every two years.
However, last month the Herald revealed the programme has never been reviewed, with the commission claiming it has been too busy so has put the review on the "back burner". The commission has said it hopes to review SkyCity's programme early next year.