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

''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.

Mr O'Donnell declined to speculate on what percentage of Catholic priests, who must vow to be celibate, were sexually active, but another Melbourne priest has separately suggested it is about half.

Asked by committee member Andrea Coote whether priests believed only sex with women counted as real sex (breaking celibacy vows), and that homosexual and child sex did not, Mr O'Donnell said: ''Sometimes.''

He said another priest told him the celibacy requirement would never change because so many priests were gay and it was ''great cover. No one asks me why I am 50 and single - they assume I am celibate,'' the priest told Mr O'Donnell.

Mr O'Donnell - a priest in Melbourne from 1975 to 1999 who resigned and later married - said sexually active priests coped with the internal contradiction by compartmentalising their professional and private lives.

In other evidence to the inquiry, Catholics for Renewal president Peter Johnstone said the church's handling of sexual abuse was directly related to its dysfunctional government. Although Australian church leaders claimed that responding to abuse was a local matter, in fact the Vatican kept strict control.

The worldwide church was governed by a 17th-century system whereby ultimate power was vested in men who were celibate, often socially isolated, usually old, unable to communicate with the faithful, and under the supreme control of a papal monarch who demanded blind obedience.

Mr Johnstone said Catholics for Renewal was an organisation of committed, progressive Catholics who represented views shared by several Australian bishops and scores of priests who were bound by rigid vows of obedience not to publicly say so.

Asked by the committee to name these bishops, Mr Johnstone said it would be inappropriate. ''If you want to see what happens to bishops who disagree, just look at Bill Morris'' (the bishop of Toowoomba sacked by the Pope last May after suggesting the church might consider revisiting the question of women priests).

However, retired bishops Pat Power of Canberra and Geoffrey Robinson of Sydney are two who have trenchantly criticised Vatican structures.

A former principal and a teacher at Holy Family School, Doveton, told the inquiry of how their careers and lives were ruined after they separately sought to protect children from the predatory parish priest, Peter Searson (now dead).

Both Graham Sleeman, a popular principal in the 1980s, and Carmel Rafferty, a senior teacher in the early 1990s, believe the Catholic Education Office and archdiocese betrayed them. Both found it impossible to get work in the Catholic education system after their whistleblowing, and both suffered years of trauma and stress.

The Doveton parish suffered six abusers in a row as parish priest or assistant priest.