"At the moment, anyone who's able to walk and talk could walk into a store and buy a Lotto ticket and be sold one," Bellringer said.
"It just normalises gambling behaviour as being something that anyone can do and is fun and fine."
Bellringer, an associate professor who is on an expert panel advising Lotto on harm minimisation, said many people enjoyed Lotto with no problems, but children needed guidance and context about gambling.
Lotto chief executive Chris Lyman said the company would be happy to introduce age restrictions but its legal advice showed it could not do that without a law change.
Internal Affairs Minister Jan Tinetti told RNZ she was uncomfortable with children buying Lotto tickets and would now consider changing the law.
Problem Gambling Foundation spokesperson Andree Froude said when she first started working in the sector she was alarmed to find there was no age restriction on Lotto tickets.
"I was absolutely gobsmacked that a 7-year-old, or 10-year-old, could walk into a Lotto outlet and purchase a Lotto ticket."
Lyman said children could buy Lotto tickets "because that's the law" but he rejected the idea they did so in large numbers. "You won't see queues of children at our stores."
He said while the R-18 restriction for Instant Kiwi was written into the Gambling Act, Lotto couldn't enforce age restrictions on other products.
"I can't step outside the law. I can't impose an age restriction," he said. "I'm not a lawmaker."
Lyman said he would be happy to see children banned from buying Lotto tickets.
"I would fully support an age restriction on all of our products. Absolutely. I see no reason why anybody under the age of 18 should buy our products. However, I don't have that power."
But Tinetti said she was willing to consider a law change to ban children from buying Lotto. "That is work that is completely on the table."
Asked whether she was comfortable that a 9-year-old could buy a Lotto ticket she said: "No, I'm not. I put that on the table right now. I'm absolutely not comfortable with a 9-year-old being able to engage in gambling."
In a 2015 study Bellringer looked at the gambling behaviours of 874 Pasifika children aged 9 and living in New Zealand.
The study found that 17 per cent, or 146 of the 874 9-year-olds, had received an Instant Kiwi scratch card as a gift, which is illegal, as the product is restricted to people aged 18 and over.
Sixty-one of the children, or 7 per cent, had bought a Lotto ticket.
The study cites previous research on New Zealand adults which found that "having first gambled before the age of 13 years was a strong risk factor for lifetime problem gambling".
In a Youth19 study, 34 per cent of high school students had gambled and 13 per cent of those students wanted to cut down.
The study, conducted by researchers at four universities and funded by the Health Research Council, surveyed 7721 high school students and found the most common form of gambling, reported by 25 per cent, was betting with family and friends.
The second most common form was buying Instant Kiwi, reported by 11 per cent.
"Young people engaging at that level really worries me," Tinetti said. "We need to be looking at how we can address that."
Instant Kiwi, considered a medium risk product because it is a form of continuous gambling, where gamblers can immediately reinvest their winnings, is the only Lotto game with an age restriction.
Lotto uses mystery shoppers to check stores are not selling Instant Kiwi to under-18s but in recent years many retailers have failed the test.
Lotto documents obtained by RNZ under the Official Information Act, show in 2016, 30 per cent of Lotto retailers failed the mystery shop test, 23 per cent failed in 2017, 21 per cent failed in 2018 and 20 per cent failed in 2019.
Lyman said this showed the numbers were improving and did not mean under-18s had been sold Instant Kiwi tickets, as the mystery shoppers were actually 18-25.
"That doesn't make it okay," Lyman said, adding the company provided extra training to retailers who failed the test and could ultimately revoke their licence to sell Lotto products.
Lotto has a harm minimisation committee to ensure the company doesn't market Instant Kiwi to children.
Its guidelines say Lotto must not feature an image of anyone under 18 on an Instant Kiwi ticket.
It also pledges not to issue a game ticket "associated with a board game that may have strong appeal to children" such as Battleship, Monopoly, Scrabble and Cluedo.
In 2018 Lotto had to pull an in-store ad for an Instant Kiwi $5 Battleship ticket, which included an illustration similar to the popular children's board game, after a successful complaint to the Advertising Standards Authority.
Many customers are still unaware of the age restriction for Instant Kiwi.
Lotto monitors "player awareness" and documents obtained by RNZ show that in 2019, 33 per cent of customers surveyed were not aware of the R-18 rating for Instant Kiwi.
Selah Hart, of Hāpai te Hauora, a kaupapa Māori public health agency working to reduce gambling harm, accepted that Instant Kiwi was Lotto's highest risk game but said age restrictions should apply to all its products.
"Why would that company want my 8-year-old son to purchase a ticket and why the heck has that not been changed," she asked.
"We have over-18 restrictions across alcohol, tobacco, and other such things. Why would that not just be an immediate thing?"
