Several contestants, including Finch and Miss USA Kristen Dalton, appeared at the HIV-awareness event just three days before last week's Miss Universe final, CNSNews.com reports.
PHOTOS: Miss Universe 2009
They were taking part in a Donald Trump-approved promotion for Population Services International (PSI), and blew condoms full of air as well as filing them with water.
Finch wowed the crowd by inflating a condom with her own breath until it burst — thus winning a challenge and provoking huge applause — but women's groups are now claiming the theatrics trivialised a serious matter.
"These 'Condom Olympics' seem quite counterproductive to raising awareness of the seriousness of HIV," Alyssa Cardova, from the Claire Booth Luce Policy Institute, told CNSNews.
"Instead of emphasizing the seriousness of the AIDS epidemic, the Miss Universe organisation has instead chosen to make a game out of it."
Rachael Finch took part in the 'Condom Olympics'. (AAP)Marshall Stowell, communications director at PSI, came to the defence of the "competition", saying contestants underwent training and games were used that were friendly to young people or those with low literacy levels.
"The point of all of those games is to teach the participants, whether they be youth in-country or Miss Universe contestants, the proper technique for using a condom, because part of HIV prevention is correct and consistent condom use," he said.
The pageant, owned by Trump, was won by 18-year-old Miss Venezuela Stefania Fernandez, with Australia's Finch finishing in fourth.