In a series of reports published by The Sydney Morning Herald in June 2026 (ahead of the second game of the State of Origin series), it was revealed that Klein had a serious gambling problem involving horse and greyhound racing, ultimately losing more than A$400,000 dollars before placing himself on the national self-exclusion register, BetStop, in 2023.^[16][17][18] The NRL first became aware of the issue in 2019 and conducted an investigation,^[16] concluding that Klein had not breached any rules because he had never bet on rugby league.^[16] As a result, he was allowed to continue officiating at the highest level, including State of Origin matches and NRL Grand Finals.^[16]

Klein's gambling reportedly escalated despite an agreement for the league (NRL) to monitor his betting activity.^[17] Integrity experts and some club officials argued that a referee with a serious gambling problem could pose a reputational and integrity risk, even without any evidence of wrongdoing.^[17] Further scrutiny followed when it emerged Klein had professional development with Racing NSW's integrity department.^[18] Throughout the controversy, both Klein and the NRL maintained that he never breached any rules, never bet on rugby league, and that his refereeing was never affected by his gambling addiction.^[18]

Following the disclosure of Klein's gambling issues, a number of commentators, former players, and coaches publicly weighed in on the matter. The Sydney Morning Herald's Roy Masters argued that Klein should be dismissed, while noting that his "masthead is not suggesting Klein or any employee of the NRL has acted improperly, and it must be assumed they would be above being swept up, even subconsciously, in such a crusade."^[19] Queensland coach Billy Slater defended Klein during a pre-Game II press conference, stating: "To be honest, I personally think it's unfair to have something personal like that be aired publicly," before adding, "I feel for Ashley... it hasn't been discussed within our camp and that's my personal position with it. I think it's quite unfair on him."^[20][21] New South Wales coach Laurie Daley echoed Slater's sentiments, saying: "I agree with Bill. It's challenging when things like that get brought up and I hope Ashley has got the right support and people around him to help navigate the period. We’ve got no issues with Ashley being part of the game."^[20] Speaking on SEN Radio, former Brisbane Broncos and Kangaroos player Corey Parker expressed an opposing view, arguing that Klein should be stood down from officiating until the matter had been fully examined by the NRL's integrity unit.^[20]