It takes just a few words being exchanged and 16 seconds on the phone to place a live bet with Sportsbet, the Supreme Court of Victoria heard on the first day of a class action that alleges the in-play Fast Code service is illegal.

A series of recordings played to the court on Monday demonstrated how short the interactions are, with users required to state their full name, provide their Fast Code and the amount they wish to bet, and answer “yes” to a single question from a Sportsbet operator before a bet can be placed.

Maurice Blackburn, the law firm leading the class action, claimed the service was illegal as key information – namely the selection of the bet – occurred online first, before being confirmed over the phone via a short three-letter code.

Every conversation opened with “Welcome to Sportsbet, you’re speaking to Mark, can I get your full name and Fast Code please.” Once the code was provided, bet information the user had already selected online was populated in the backend system visible to the operator, who confirmed the live odds and asked how much the caller would like to bet. Every call ended the same way, with the operator declaring: “Bet’s on.”

Under Australia’s Interactive Gambling Act, placing live bets during a sports game is banned to minimise the scope of harm of severe gambling addiction, and the risk of match-fixing. However, phone calls are exempt, with agencies arguing that speaking to an operator slows down the betting speed.

Lawyer for the plaintiffs Philip Solomon told Justice Robert Craig on Monday the act required live bets to be placed by voice call, meaning an interaction consisting “wholly of spoken conversation between individuals”.

“Wholly doesn’t mean principally and wholly doesn’t mean ultimately,” he said. “At a broad level, the policy idea is to slow down the transaction. From these videos and other videos, your honour gets a sense of the sort of speed with which different steps occur.”

Over the next two weeks, Solomon is expected to argue that by representing that the Fast Code service was lawfully provided, Sportsbet engaged in misleading and deceptive conduct under the Australian Consumer Law.

He foreshadowed on Monday that for the most part, the case was likely to be argued over statutory construction, not facts.

Lead plaintiff Jeremy Bergman is alleged to have lost around $2300 placing bets via the Fast Code service, which is still in use on Sportsbet’s app and website.

As part of the class action, Maurice Blackburn is pushing for the betting company to remove the feature and refund anyone who made a losing live bet using it between December 2018 and December 2024 – which could be in the hundreds of thousands of people. The law firm is also pursuing a similar class action over in-play Fast Code services offered by Neds and Ladbrokes.

Solomon is expected to call several witnesses to the box for cross-examination over the coming fortnight, including other users of the service. He said the outcome of the trial would have important implications for sports betting at the policy level.

Sportsbet denies the allegations and is defending the claim.