Nine Australian Olympic athletes were detained overnight and fined for tampering with their identity cards to be able to watch their home country's basketball semi-final, officials said Saturday.

The athletes "had tampered credentials" to get into the arena where Australia was facing Serbia in the basketball at the Olympic Park late Friday, Rio police said in a statement.

Nine were charged with "the crime of use of false documents," the statement said. They were taken before a judge and let off in return for payment of 10,000 reais (US$3,120)fines.

They included members of the cycling, rugby, archery, hockey and rowing teams, the Australian Olympic team said in a statement.

During an all night court session, the athletes were offered the chance to have charges dropped in exchange for the fines, with their passports being kept until payment is made, Australian team spokesman Mike Tancred said.

Otherwise the athletes would have been forced to stay in Brazil at least three weeks, pending trial, and face a potential jail term if found guilty.

"The athletes were supporting their teammates, they were not attempting to defraud anyone, no-one had suffered a material loss and no-one was harmed as a result of the incident," Australia's deputy team leader Fiona de Jong said.

A spokesman for the Rio Olympic organizers called it a "minor incident."

"The athletes were required to give evidence and were released following accordance with the law," he said.

International Olympic Committee President Thomas Bach speaking at a press conference on Saturday declined to comment on the incident saying he hadn't been briefed on the details.

The incident followed a drama played out in the Brazilian and international media over the claim by four US swimmers, including superstar Ryan Lochte, to have been robbed at gunpoint in Rio. Three were detained on accusations of making a false report and later accepted that their account had been fabricated.