The regulator for almost all sports betting companies in Australia has admitted that fines worth tens of thousands of dollars for serious misconduct have little impact on a booming industry now worth almost $50bn a year.

The Darwin-based Northern Territory Racing Commission (NTRC) has also told a parliamentary inquiry that Newscorp-backed wagering platform, Betr, has been “seriously put on notice” about its licence being cancelled should it again breach harm-minimisation policies.

Almost all sports betting companies, with the exception of Tabcorp, are based in the Northern Territory for historical tax purposes, meaning they are regulated by the commission. Most of these companies are also multinationals, including Sportsbet, Ladbrokes and Bet365.

The commission’s chair, Alastair Shields, told the parliamentary inquiry into online gambling harm on Tuesday that relatively low fines are an issue that will hopefully be addressed by the NT government once a five-year review of legislation is complete.

Betr was recently fined $77,000 for directly contacting and encouraging a man who had banned himself from gambling to open a new account with Betr, shortly before the company launched last year. His contact details were retained by someone who had previously dealt with him at another gambling company.

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“The vast majority of [companies] have significant turnovers and $77,000 would not be a significant impost,” Shields told the inquiry.

“They have been very, very seriously put on notice that if you do this again we won’t consider a fine, we’ll consider a suspension or a cancellation of your licence, which is a pretty serious response.”

The NTRC has not suspended any gambling operators since 2018, despite serious breaches, telling the commission that threats to do so had improved behaviour.

In a separate case, the NTRC fined Bet Nation $13,770 after it emailed gambling promotions to 7,713 people, including those on a self-exclusion register. A Tasmanian man who had tried to quit gambling nearly 50 times described the fine, worth half the maximum amount, as “disgusting” and ineffective.

Freedom of information documents obtained by the ABC last year reveal gambling companies have threatened to leave the territory if taxes are raised. The cash-strapped NT government, which recorded a $1.1bn deficit last year, receives licensing fees from the companies. Hundreds of staff are also based in the NT.

Some critics of the NTRC, including academics Matt Stevens and Samantha Thomas who appeared before the inquiry, argue the regulator has not kept pace with the significant growth of the gambling industry and is underfunded.

Ten years ago, sports betting companies in the NT had a turnover of $5.7bn. That figure has now increased to $48.3bn thanks to the popularity of smartphone apps, official partnerships with major sporting codes and high-profile advertising.

“The Northern Territory is a small jurisdiction, and consequentially, there is a closeness between politicians, industry and public servants,” Stevens said.

Shields told the inquiry that a former chair of the NTRC is now the chair of the major racing and gambling venue Darwin Turf Club, although he denied any conflict of interest. He also said a former NTRC employee who worked in the gambling systems division has started a business related to his former employment.

The inquiry has also heard complaints about the volume of sports gambling advertisements. ACT attorney-general Shane Rattenbury said he would welcome a complete ban on sports gambling advertisements, arguing they are unduly targeting young men who are vulnerable to gambling harm.

“We would like to see far greater restrictions, if not an outright ban on a range of gambling advertisements, particularly during hours where younger people are watching but across the board,” Rattenbury said.