Australia's largest casino has been fined A$300,000 (£160,000; $225,000) for tampering with its slot machines to limit betting options.
The penalty given to Melbourne's Crown casino is believed to be the largest of its kind issued by regulators in Australia, anti-gambling advocates say.
Regulators found that buttons had been covered up on the slot machines, known locally as poker machines or pokies.
Crown has been hit by other damaging allegations in recent times.
The Victorian Commission for Gambling and Liquor Regulation (VCGLR) said the casino had used "blanking plates" on 17 machines during a trial programme last year, meaning that gamblers were left with only maximum and minimum options.
"This is the largest fine the commission has issued to Crown and reflects the seriousness with which it considers the matter," it said in a statement.
Gamblers lose more money per head in Australia than in any other nation.
Breaches 'not deliberate'
The regulator acknowledged that the trial had not affected the ratio of returns to gamblers, and that the casino had not deliberately intended to breach laws.
However, it said the penalty should deter casino operators "from varying machines without approval".
Crown had previously denied altering its machines, before admitting to doing so during a three-week period.
"While Crown Melbourne's position throughout this process was that the Gaming Machine Trial did not require the prior approval of the Commission, Crown Melbourne respects the Commission's decision, which brings this process to a close," it said in a statement on Friday.
Last year, MP Andrew Wilkie presented whistleblower statements to parliament which alleged the casino had altered its machines and breached player regulations.
After the ruling on Friday, Mr Wilkie said: "This is a very serious offence for which Crown should stand condemned.
"However, I do not accept Crown's explanation that this was only a trial, because there is an abundance of evidence that the practice has been more widespread."
Crown won a landmark court case in February against a former gambling addict who argued that she had been misled by "deceptive" design features in one of the casino's gaming machines.
The source: BBC NEWS