Hans Küng is appealing to priests and churchgoers to confront the Catholic hierarchy, which he says is corrupt, lacking credibility and apathetic to the real concerns of the church's members.

In an exclusive interview with the Guardian, Küng, who had close contact with the pope when the two worked together as young theologians, described the church as an "authoritarian system" with parallels to Germany's Nazi dictatorship.

"The unconditional obedience demanded of bishops who swear their allegiance to the pope when they make their holy oath is almost as extreme as that of the German generals who were forced to swear an oath of allegiance to Hitler," he said.

The Vatican made a point of crushing any form of clerical dissent, he added. "The rules for choosing bishops are so rigid that as soon as candidates emerge who, say, stand up for the pill, or for the ordination of women, they are struck off the list." The result was a church of "yes men", almost all of whom unquestioningly toed the line.

"The only way for reform is from the bottom up," said Küng, 84, who is a priest. "The priests and others in positions of responsibility need to stop being so subservient, to organise themselves and say that there are certain things that they simply will not put up with anymore."

Küng, the author of around 30 books on Catholic theology, Christianity and ethics, which have sold millions worldwide, said that inspiration for global change was to be found in his native Switzerland and in Austria, where hundreds of Catholic priests have formed movements advocating policies that openly defy current Vatican practices. The revolts have been described as unprecedented by Vatican observers, who say they are likely to cause deep schisms in the church.

"I've always said that if one priest in a diocese is roused, that counts for nothing. Five will create a stir. Fifty are pretty much invincible. In Austria the figure is well over 300, possibly up to 400 priests; in Switzerland it's about 150 who have stood up and it will increase."