The nine, variously rowers, archers, cyclists and a hockey player, were detained when trying to attend the Australian basketball team's semi-final against Serbia. After an all-night process, they were released at dawn after AOC chief executive and deputy chef de mission Fiona de Jong negotiated with authorities for them to be fined rather than proceed to court where the Australians would have been liable for jail terms.

In short, someone had supplied them with stickers to put on their accreditation placards, giving them access to the basketball court.

That someone, presumably a team official, will not be identified until an internal investigation is complete. "It's traditional not only in Australia, but in other countries as well: putting a sticker on your accreditation with another venue code on it," said chef de mission Kitty Chiller on Saturday morning Rio time.

"I'm very disappointed that they had to go through what they did go through last night. I think it's very important to note that the athletes were not at fault. We have and will continue to provide as much support [as we can] to them and their parents." She said they would not be further punished by Australia.

The messy saga has its roots in two Olympic sore spots. One is the fact that the International Olympic Committee, a private body, insists on imposing its own laws wherever it lands.

The Australians' offence was relatively trivial, akin to holding up the fence wire to get a mate into the footy. Most of the venues are far from full anyway, and gatekeepers are not particularly vigilant.

Yet at the IOC's insistence, tampering with accreditation is a criminal offence in Brazilian law, carrying a potential jail term of up to five years. The law is part of a wider scheme to combat ticket scalping at the Games.

De Jong was diplomatic. "We are in Brazil, so we understand that tour athletes need to adhere to Brazilian law," she said. "The concept of falsifying a document is probably a universal principle. The athletes understood that they perhaps had made a mistake, and understood that perhaps there would be consequences for that."

The other aggravation is a growing feeling that Brazilian authorities - upset at the poor international reception for Rio's Games, and angry at the antics of American swimmer Ryan Lochte - are seizing every opportunity to hit back. As the Olympics are a private event, this matter could have been sorted out between Olympic and Australian authorities at the venue, but was not.

Again, de Jong was tactful. "Our athletes were dealt with entirely fairly. They were looked after," she said. "It took some time, of course, and it was late at night, but in terms of the process, we have no complaints."

The nine athletes charged with falsifying a document were: cyclists Ashlee Ankudinoff and Melissa Hoskins; rugby sevens captain Ed Jenkins; archers Alec Potts and Ryan Tyack; rowers Olympia Aldersey, Fiona Alber and Lucy Stephan; and hockey player Simon Orchard. A tenth, cyclist Matthew Glaetzer, was not charged but detained as a witness. He was not required to provide a statement to police.

The AOC later released a statement apologising to the athletes for their trauma.

"For legal reasons I am not in a position to elaborate except to say it is important to know that the Australian athletes were definitely not at fault. I am very disappointed our athletes had to go through what then went through last night," Chiller said.

The International Olympic Committee wants more information about the matter before deciding whether to take any action. Asked about it on Saturday afternoon in Rio, IOC president Thomas Bach said:

"I got information only this morning so I cannot yet comment. We will have to look into this."

Meantime, Australian swimmer Josh Palmer will make a statement to Rio police today concerning his claim to have been robbed during the week. "We will do everything in our power to protect Josh, and protect our athletes," said Chiller. "Hopefully, they can all be on that charter [flight home] on Monday night."