One of the world's largest gambling companies has been fined for an "extremely serious breach" after it was caught luring new customers with bonus cash offers worth as much as $1,000.

Entain Group — which owns dozens of international gambling brands including Ladbrokes, Sportingbet and Neds — holds a sports bookmaker's licence in the Northern Territory.

Under the NT's Code of Practice for Responsible Service of Online Gambling, companies are forbidden from offering credit, vouchers, or rewards to incentivise people to open new accounts.

But the NT Racing Commission, which regulates the industry, has found Entain violated its licence by giving punters QR codes that activated "bonus cash" offers when they signed up to new accounts on the Neds website.

"The commission considers the offering of incentives to non-existing customers to open a betting account is an extremely serious breach of the 2019 code," it stated in a decision published this week.

An investigation into the company's actions was launched after a commission member witnessed a conversation between a Neds representative and a racegoer at Darwin's Fannie Bay racecourse on July 31.

"The allegations were that during the course of the conversation the [representative] stated that bonuses were available to that individual, or any others who opened a Neds account using the QR code on his business card," the commission said.

The commission member obtained the same business card and after scanning the QR code and opening a new account, they were offered three bonus cash options, ranging from $150 to $250.

But a list of more than a dozen punters who signed up to the deal that day showed one received a bonus of $1,000 after depositing the same amount in their new account, while another received $400.

Entain confirmed two business development managers representing Neds were at the racecourse, but both denied that bonus bets were offered to non-existing customers.

Instead, the pair claimed they were offering matched deposits to existing customers, which is allowed.

Despite their denials, Entain told the commission it had terminated the services of the pair for going against their training regarding sign-up inducements.

Entain argued that their termination should be the end of the matter.

But the commission said Entain, which had provided the businesses cards to the Neds representatives,  was at fault.

"The commission is of the view that these business cards have been issued by Entain to Neds [representatives] for the main purpose of inducing non-existing customers to open an account on the promise of a bonus cash offer.

"There seems to be no other plausible reason to include a QR code which automatically provides bonus cash offers upon a new account be opened."

The commission noted Entain, which was previously called GVC, had been fined in 2019 after its brand Ladbrokes was found to have handed out 400 "cash in cards" worth $20 each to potential new customers.

Despite the previous breach, it determined not to suspend or cancel Entain's current licence, and instead issued it with the same maximum fine of $26,690.

However, the commission warned Entain that it may take more substantial action if further breaches occur.

"Should Entain, or any of its related businesses, breach [the] Code again in the future, the Commission will consider carefully whether other disciplinary options … should be imposed."