Cain spoke at a tele-town hall sponsored by TheTeaParty.net, while his campaign manager, Mark Block, made a similar allegation in an interview with Fox News, Politico reported.
"We've been able to trace it back to the Perry campaign that stirred this up in order to discredit me," Cain said. "The fingerprints of the Rick Perry campaign are all over this, based on our sources."
Politico broke the story that the National Restaurant Association settled with two female employees who said Cain had sexually harassed them while he was the trade group's president in the 1990s. Cain and Block also attacked the publication.
"Both Rick Perry and POLITICO did the wrong thing by reporting something that wasn't true," Block said.
Cain blamed Curt Anderson, a strategist now working for Perry. He said he told Anderson about one harassment allegation.
Anderson issued a statement denying he was responsible for putting the sexual harassment story out.
Roy Sullivan, a spokesman for Perry, said no one in the campaign knew about the allegations until they read them in Politico. Anderson denies being the source of the story.