Twenty-one young women were accused of revealing their experience in the South against a code of silence to which they swore, said Kang Chol-hwan, who himself escaped the North in 1992, quoting North Korean defectors now in China.
Kang is the author of the book The Aquariums of Pyongyang about his own experience of torture and forced labour in a North Korean prison camp.
He had a personal audience with US President George W. Bush last year during which they discussed human rights abuses in the North.
"I heard that the women violated the oath not to disclose what they saw and heard in the South," Mr Kang quoted one of the defectors who had served in the camp as saying in an article he wrote for the main daily newspaper Chosun Ilbo.
The group of cheerleaders grabbed attention in South Korea last year at an Asian athletics event near Seoul with their precision choreography and endless smiles.
The camp in Taehung had been known to hold financial criminals but more recently began taking political prisoners, Mr Kang later said by telephone.
The camp is in rugged mountains in the north-eastern part of North Korea.
Mr Kang quoted another North Korean defector as saying the cheerleaders were picked from elite college graduates and propaganda troops.
Survivors of prison camps have given testimony about torture, relentless propaganda sessions, forced labour and in some instances lethal biological testing on live human beings.