Ashley Klein will walk out to referee Wednesday night's Game 2 of the State of Origin series at the Melbourne Cricket Ground after a report made by The Sydney Morning Herald revealed his gambling habit.

Since then, more information has come to light.

Nine News has since learned Klein allegedly approached at least three fellow match officials for loans during the depths of a punting habit that drained more than $400,000 from his pockets on horses and greyhound racing, according to the SMH article.

"He reached out to me a few years back and asked for a $5000 loan - said he was going through some tough times," one former ref revealed to Nine.com.au.

"I know of at least two other match officials who he also hit up.

"He didn't say what it was for - but it was pretty obvious."

Days before the Herald's story ran, Klein was already Queensland's public enemy number one after sending off Maroons fullback Kalyn Ponga in the series opener for a shoulder charge that knocked NSW winger Tolutau Koula out for the match with a failed HIA.

It's believed that the NRL first got wind of Klein's gambling, triggering an internal review years before the Herald's story broke.

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Klein shut down his betting accounts and placed himself on the national self-exclusion register, BetStop, in 2023.

The NRL's investigation found no breach of NRL rules or policy.