New figures show a sharp rise in gambling problems linked to Lotto, and health officials blame big jackpots.
The figures show more than 12 per cent of problem gamblers cite the Lotteries Commission as their main gambling outlet, up from 8.8 per cent in a survey three years earlier.
While pokies in pubs and clubs still lead problem gambling statistics, the figures show more problem gamblers associated with Lotto since its big jackpot of $37 million in 2009.
The Ministry of Health, in a consultation document for setting the gambling levy, said "these increases are probably related to the increased frequency of large jackpot prizes and the enhanced appeal of large jackpots in difficult economic times".
The increase comes as Government ministers consider official advice to increase funding from the Lotteries Commission to services helping to treat problem gamblers.
The Gambling Commission has told ministers Chris Tremain and Peter Dunne they need to change the formula for funding the problem gambling levy, upping the Lotteries Commission's share from $4 million to $5.4 million - a rise of 36.5 per cent.
The Lotto body has resisted the increase, saying it would reduce the money the Lottery Grants Board distributed to community groups.
Lotto's rise in problem gambling figures was first signalled by Maori health provider Hauora Waikato.
The ministry consultation document also suggests that easy access to Lotteries Commission products online could be part of the problem.
The figures come amid calls for health warnings to be placed on gambling products - including Lotto.
Hauora Waikato general manager Aroha Waipara-Panapa, a clinical psychologist, said Lotteries Commission games were the friendly face of gambling and "contribute to the acceptability of gambling in general".
A warning would "advise people that buying a Lotto ticket is a gambling activity and it can lead or contribute to gambling harm".
Ms Waipara-Panapa said Lotto was an easily accessible and relatively cheap form of gambling.
Hauora Waikato had heard of families going without basic food items like milk and bread to "be in to win".
The claim was supported by a Synergia report to the Gambling Commission three months ago that said Lotteries' products were the second most common form of gambling to cause an argument in a family or to cause someone to go without.
It was cited in 14 per cent of cases, after pokies at 52 per cent.
A Lotteries Commission spokeswoman said the increase in gamblers with problems was offset by the decrease in people affected by a gambler's behaviour.
"Taking gamblers and 'affected others' together, the percentage of new clients citing NZ Lotteries has not changed materially over the three years."
She cited different figures, saying: "There has been virtually no change in the sector share of problem gambling presentations since 2009.
"It has been our belief that if there had been a fundamental shift in the gambling behaviour of problem and at-risk gamblers, this would have been borne out in the data for people seeking help."
New problem gamblers
2008-09 4.7 per cent
2009-10 6.5 per cent
2010-117.3 per cent
Problem gamblers citing Lotto as main game
2008-098.8 per cent
2009-1011.5 per cent
2010-1112+ per cent
Source: Ministry of Health