Many Catholic priests take a flexible approach to celibacy, tolerated by church leaders, and some believe sex with children or men does not count, a former Melbourne priest said on Wednesday.

''An enormous number of priests struggle with celibacy,'' Philip O'Donnell told the state inquiry into how the churches handle child sex abuse.

Former priest Philip O'Donnell. Credit:Ken Irwin

''There's a tolerance for imperfection in celibacy, and that may have led to a lessening of outrage at sex with children.''

He said he had no training about celibacy in the seminary and that many priests were ill-equipped. ''Chosen celibacy is a gift, but mandatory celibacy is for many priests a millstone,'' he said.