A Kiwi gamer says he has spent about $16,000 on loot boxes, which could be described as virtual treasure chests, in online video games.
Games like Counter-Strike and FIFA, now EA FC, allow players to spend real money to open them and have a chance at winning in-game rewards.
Problem gambling groups are worried about the sums of money being spent on loot boxes, which they say operate in much the same way as real-life gambling.
Jacques Strydom got hooked on loot boxes while playing the hugely popular online first-person shooter Counter-Strike.
It was the thrill of clicking on and opening the boxes that drew him in, rather than the prizes themselves.
Because he was only spending a few bucks at a time he felt he wasn't a big deal, but it all added up.
"If you put all that money aside in a bank account, I would have had about 16k now, that I could have put towards a home deposit or something."
Strydom said he felt "terrible" whenever he looked at the amount of money he'd spent.
He was in no doubt that loot boxes were designed to be addictive.
He could no longer trust himself with a credit card, so he left it to his wife to look after, he said.
"As a person with an addiction, you'd always find some sort of 'I'll just cut on this this week so I've got a little to spend'... it's just easier to just give it all to her."
Popular gaming personalities often post highlight reels of themselves opening loot boxes, and their over-the-top reactions should they get something good.
For example, duo Twosync open loot boxes in football game EA FC. Their videos are loud and colourful with fast-paced editing and sound effects. And there's a lot of screaming when one of them gets a good player.
Strydom said these sort of videos glamorized opening loot boxes. He has two children who also play video games and he tells them not to watch them.
"They only show you the good stuff they get, they don't show you all the thousands they've spent before that."
Mark was also a keen Counter-Strike player who had spent about $5000 on loot boxes.
The way the boxes worked was reminiscent of real-life gambling, he said.
"When you open a loot box, you get the scrolling animation, as if you're sitting down at the pokies and watching what you could be getting go past."
Mark said his friend whom he opened the boxes with would always be sure a big win was just around the corner.
"He would say 'I'm due for a knife', which is like the most expensive thing in Counter-Strike, and I'm sitting there like 'you aren't due anything, every time you click it's completely random what you get'."
Pasifika gambling counselling service Mapu Maia chief executive Pesio Ah-Honi said it was concerning that "gambling mechanisms are embedded in kids games that are not regulated or don't have age restrictions on it".
The agency has done research into the link between gaming and problem gambling for Pacific youth, and suggested education as part of the solution.
"I think there's a lot of ways that we can use education as a platform to raise awareness, and to also get feedback from the community ... around what services are needed ... for our young people in particular."
Ah-Honi also wanted to see a labelling system for games that contain loot boxes, so parents knew what their kids were playing.
A spokesperson for Electronic Arts, the creators of FIFA and EA FC, said it believed that optional in-game purchases played an important role in giving players a choice in how to play the game.
EA did not target minors or encourage them to spend money, they said, and the consoles their game was available on had robust parental control options.
Loot boxes which do not allow players to win actual money should not be considered gambling, they said.
Research into the connection between gaming and gambling is in the early stages they said, and there was no conclusive scientific evidence that loot boxes caused harm.