Victoria’s gambling regulator has handed casino-operator Crown a $300,000 fine for the illegal altering of poker machines.

The Victorian Commission for Gambling and Liquor Regulation (VCGLR) launched an investigation after it found blanking plates placed over certain buttons poker machines last year.

The buttons blanked out betting options so that only the minimum and maximum bets were available.

“The blanking plates concealed play line options so that only minimum and maximum betting options were available,” VCGLR said in a statement.

“The commission considers that the way in which Crown used blanking plates in the trial constitutes a variation to the gaming machines and therefore required approval by the VCGLR, and that Crown's failure to obtain approval means it has contravened the Gambling Regulation Act 2003.

“The contravention was not deliberate. The decision to conduct the trial was made by a small group of Crown staff who did not believe approval was required and who failed to consult internally, or with the VCGLR, to check whether approval was required before commencing the trial.

“Crown acted quickly to cease the trial following a complaint and before the matter was raised with the VCGLR.”

Whistleblowers had alleged that the change increased punter losses by forcing them to make higher bets, but regulator found the trial did not affect how much wagered money was paid back to players.

The state’s Minister for Gaming and Liquor Regulation Marlene Kairouz said it was an “unacceptable” breach.

“The independent commission has conducted their investigation, and appropriately, issued a significant penalty for this breach,” she said.

Charles Livingstone, a researcher focused on the social effects of gambling and gaming policy at Monash University, said the it was a virtually meaningless fine.

“A damp feather would be a fairly significant penalty in comparison to this fine in my opinion,” he told the ABC.

“I suppose the regulator thinks that by suggesting a $300,000 fine, that that will make people think that it's a big deal. It's not a big deal. That's just small change to these people.”