Australian swimmers Emma McKeon and Josh Palmer have been banned from the closing ceremony after failing to return to the Olympic village after a night out with their teammates.
In a statement, the Australian Olympic Committee said the swimmers left a nightclub in Copacabana in the early hours of the morning.
McKeon decided to spend the night with friends at a hotel nearby and failed to inform team management officials.
McKeon won a gold medal in the women's 4x100 metres relay, silver in the 4x200 metres relay and the 4x100 metres medley relay and bronze in the 200 metres freestyle.
Palmer chose to continue drinking elsewhere and was later found "disoriented" by two businessmen.
He did not have his phone or his wallet and he reported a man forced him to withdraw $1000 from an ATM.
The businessmen took him to the Australian consulate where swimming team leader Wayne Lomas later picked him up and took him back to the village.
Chef de Mission Killy Chiller has imposed a curfew on both athletes, who must now be within the village before 8am and after 8pm, along with the closing ceremony ban.
Swimming team management has also imposed a curfew on all its athletes of 2am.
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"Palmer and McKeon's behaviour was unacceptable and they breached disciplinary protocols," Chiller said.
"I have raised the need for the swimming team leader to ensure he is aware of his athletes' whereabouts when leaving the Olympic village and that the swimming team observe the 2am curfew.
"Given the security problems we have encountered over the past few weeks I find the behaviour of the disciplined athletes disrespectful to the remainder of the team."
Chiller said she was the security protocol was in place for the entire team to make sure they all came home safely and the 2am curfew was not a punishment.
"It's us ensuring, and swimming ensuring, that the safety and security of all our team members remains paramount," she said.
"This could've ended up a lot worse and I do not want any athlete to put themselves in a position - we know what goes on Copa and Ipanema, we have recommended to athletes that they go to Baha.
"I do not want to have to call a parent and tell them that their child has been robbed, mugged or anything worse.
"Everything that we put in place is not the fun police, it's not party poopers, it is ensuring that their safety remains paramount in their minds as well as our's."
Both swimmers have apologised for their behaviour and Palmer has chosen not to make a formal complaint about the alleged robbery.
