A computer system which predicts problem gamblers by their spending habits is among SkyCity's offerings over the proposed national convention centre.

The system - which the casino first raised five years ago - would allow SkyCity staff to help people who might become addicts before they develop a problem.

It will replace the tools used by casino staff now, which include looking for gamblers crying or falling asleep in front of gaming machines.

The offer has been linked by SkyCity to its negotiations over the $350 million international convention centre. SkyCity has offered to pay for it in return for gambling concessions at its Auckland casino.

Prime Minister John Key has come under fire after it emerged he solicited SkyCity's bid for the centre, which the casino wants to trade for more poker machines and gaming tables, along with an early extension to the licence for its Auckland casino.

There have been few specific details on the negotiations between SkyCity and officials at the Ministry of Economic Development.

Last night, SkyCity revealed it had included plans to improve its host responsibility programme as part of negotiations over the centre.

SkyCity chief executive Nigel Morrison said the company would be the "first commercial casino in the world" to use software to predict problem gamblers.

He said the "sophisticated software tool" would analyse historical player behaviour. It would pick out players who were "potentially high-risk and in need of monitoring".

The software would also find those who were high-risk and in need of help from host responsibility staff.

The casino company also offered a voluntary system for poker machines to let gamblers set spending and time limits before they play. He said the company would become the first pokie operator in the country to use the technology.

The Herald understands the software aimed at finding problem gamblers has been developed by Canadian Tony Schellinck and relies on loyalty card data collected by SkyCity. Dr Schellinck, who runs a company called Focal Research Consultants, is regarded as a world expert in mining information from loyalty cards as a means of better understanding those who use them.

He and his company emerged in a Gambling Commission decision from 2007 when SkyCity presented its new host responsibility programme.

The commission decision placed the company on notice it was legally responsible for preventing and minimising problem gambling on its premises. The decision stated the programme, which was meant to be reviewed every two years, was a condition of SkyCity's casino licence. It has yet to be reviewed.

An academic paper by Dr Schellinck published in the Journal of Gambling Issues in November said tests showed the software tool made detection of problem gamblers far more effective.

Problem Gambling Foundation chief executive Graeme Ramsey said he wanted to know why it took five years for the work to be completed.

He said SkyCity should tell the public the information it had gleaned from loyalty data which it had collected for years.

Mr Ramsey said he believed SkyCity's data would reveal the company made $90 million a year from problem gamblers through its poker machines.

The figure was based on each pokie bringing in about $140,000 a year - in line with SkyCity's financial reports - and Australian government findings that 40 per cent of pokie users were at risk of addiction.

"It has taken five years and it is only now they have brought it out. In that time, they have done a lot of analysis. Why can't we see that?"