The territory's Ombudsman has told punters - who lost $3.8 million in the collapse - that their complaints against the ACT Gambling and Racing Commission (GRC) over its dealings with the bankrupt bookie will not be pursued.

The Ombudsman's office has found that directors of the defunct gambling house misled authorities about its true financial position.

Some customers are furious, branding the Ombudsman a ''toothless tiger'' and demanding to know why it took 20 months to reach the finding. But the GRC says it is not surprised by the result and that it was always confident its conduct would be vindicated.

Sports Alive collapsed with debts of more than $14 million, including $3.8 million to 18,000 betting customers, and a Victorian Supreme Court decision in March virtually ensured they would get none of their money back by putting the punters behind secured creditors for refunds of money owed.

The collapse is being investigated by fraud squad detectives in Melbourne, where the betting agency conducted most of its business, and by the Australian Securities and Investments Commission.

A group of angry gamblers have been waiting since 2011 for the Ombudsman to investigate their claims that slack oversight of the bookie by the GRC was a key factor in their money being lost.

But the Ombudsman's senior investigation officer has written to the complainants, telling them of no further action from her organisation.

''The commission relied on information supplied by Sports Alive over a number of years and was assured by that information,'' the officer wrote. ''The assurance provided to the commission was later found to be unreliable.

''The commission has reviewed what happened in this case and taken a number of steps to improve its regulation of sports bookmakers.''

GRC chief executive Greg Jones said he was ''not at all'' surprised by the Ombudsman's findings.

''The commission has held all along that the information provided by Sports Alive was deliberately false and misleading,'' he said. ''Having discovered that, post liquidation, we provided information to the Victorian police on the potential fraud as well as information to ASIC.''

But account holder Dennis Tuan-Mu, who led the punters' protests since the bookie's collapse, was scathing.

''The final reasons provided by the Ombudsman are brief, generic and provide no basis for how they reached their ultimate outcome,'' Mr Tuan-Mu said. ''They failed to comment on how the ACT GRC didn't even perform basic and rudimentary checks of Sports Alive's multiple breaches at any time over eight years, any one of which would have alerted them to problems.''

A spokeswoman for the Ombudsman said the complaint could not be finalised until after the Victorian Supreme Court handed down its judgment.