Around AU$5 million (US$3.08 million) will be refunded to spectators of last year's Boomers vs. Team USA two-game series at Melbourne's Marvel Stadium after the Australian consumer watchdog found that promoter TEG Live made false claims about its seating plan.

The 20,000 refunds will be paid out to those who purchased floor-level seating for the games. Despite a mock-up depicting tiered seating, the seats used were in flat rows, lower than the court and, in some cases, more than 30 metres from the action.

"Consumers paid a premium for floor-level seats, ranging between $895 and $3,995 for a hospitality package, and may have done so as a result of misleading seating advertising," said Rod Sims, chairman of the Australian Competition and Consumer Commission. "In our view, TEG Live's conduct was unacceptable."

The ACCC had stepped in already in August, ahead of the two highly anticipated FIBA World Cup warm-up games in Australia, instructing TEG Live to offer refunds to any ticket holders who felt misled by the advertising campaign or let down by the inadequate seating. Many spectators didn't take up the offer at the time.

On Tuesday, TEG Live accepted that it would need to provide refunds to all ticket holders who sat on the floor, taking full responsibility for the debacle.

"As this was the first time a basketball game has ever been staged in a football stadium in Australia, we created this background image," a statement from TEG Live read, referring to the tiered seating visuals. "Ultimately that mock-up did not reflect the actual seating arrangements. This was a mistake on our part."

The ACCC also looked into potential false advertising of the event, with many of the players TEG Live used to market the games, such as Kevin Durant, LeBron James and Stephen Curry, not making the trip to Australia.

"We are concerned consumers may have purchased tickets believing many of these advertised high-profile players would be playing, when in the end, this was not the case," Sims said.

However, he added: "The promoters did not have reasonable grounds in most cases for representing to consumers [that] they would play or be available to play."

TEG Live's statement echoed Sims' comments.

"We acknowledge some fans were disappointed that the USA Men's Basketball team that competed in Australia in August did not include some of the NBA's biggest stars," it read. "Based on the information provided to TEG Live by USA Basketball, we had expected these stars to play."

TEG Live will automatically refund fans who purchased tickets after Aug. 15, 2018, if they previously requested a refund because of the altered team lineup. No other refunds will be offered due to the changes to Team USA.

In the coming months, the company is expected to contact and refund the 5,000 fans who purchased the 20,000 floor seats to the games.