Regulators are being called on to impose greater controls on video game "loot boxes" after researchers found young players are being exposed to gambling-like behaviours.
Loot boxes give players random digital rewards - such as weapons or costumes - and can be acquired through gameplay or by spending real cash.
Gamers favour them because they not only give a competitive advantage or power, some also have the potential to be on-sold for money.
Analysis of 22 well-known games containing loot boxes - such as FIFA 18, Madden NFL 18 and PlayerUnknown's Battleground's - found 10 met a five-point criteria to be considered gambling.
All allowed for underage players to access the loot box systems, according to a paper published in journal Nature Human Behaviour.
The researchers say young males, who make up a considerable portion of the video-gaming population, are more likely to develop pathological gambling behaviours if they're exposed to gambling at a young age.
They've called for an increase in the minimum age of players to 18, more warnings on games about digital reward mechanisms, along with continued research into the effects of long-term exposure to loot boxes.
Co-author Dr Aaron Drummond at Massey University's School of Psychology dismissed comparisons between loot boxes and a lucky dip, saying the games-rewards were potentially addictive and dangerous.
"We're not just looking at a difference between two toys that are functionally equivalent and about the same cost. We're talking about the possibility of potentially winning something that will make you a much better player," Dr Drummond told AAP.
"So there is a clear incentive for them to keep going back to these loot boxes to try and get these powerful competitive rewards."
Dr Drummond said some loot boxes operate very similarly to a poker machine.
"You pay real-world money to get a randomised reward which may be of high-value or it may be of low-value to you after you receive it," he said.
"So in that sense, they're, on face value, very similar to gambling."
Dr Drummond said the Netherlands and Belgium had recently introduced legislation to control loot boxes.
While the US and UK have ruled random digital rewards are not gambling, he said.
"There's an emerging policy discussion and clearly that's going to happen across multiple countries," he said.
Games developers may beat regulators to the punch.
American video game maker Electronic Arts Inc. recently used E3, the world's largest video game conference, to signal that its latest offerings won't contain loot boxes.
