Jakub Pankowiak's story of sexual abuse by a local priest is shaking up Poland's Catholic hierarchy, amplifying calls for full transparency after decades of cover-ups in the former communist country.

Pankowiak, an organist's son and a young boy at the time, recalls that Father Arkadiusz Hajdasz was "friendly, open, smiley" when he arrived in the town of Pleszew.

"It started with tea and cookies... until one day he sat down and just started kissing and fondling me," Pankowiak told AFP in a phone interview.

"I was speechless to the point of no reaction. I just waited for it to end," said the 35-year-old who still recalls the priest's bad breath and pimply ruddy cheeks.

Pankowiak, now a musician and lecturer, said Hajdasz molested him hundreds of times, as well as his younger brother Bartlomiej and others.

The siblings tell their story in a documentary called "Hide and Seek" by Marek and Tomasz Sekielski.

Viewed seven million times on YouTube since its May release, it has ignited debate on the issue of clerical sex abuse in Poland.

While the subject has long been taboo in the predominantly Catholic country, Pankowiak and others believe the tide is turning and could lead to the kind of church shake-up already seen in Ireland and the United States.

- Relic of communism -

The documentary says Hajdasz was shuffled from one parish to another and carried out acts of abuse for a quarter of a century, allegedly with tacit protection from higher-ups including bishop Edward Janiak.

Since the film's release, the Vatican has ordered an investigation into Janiak and taken the rare step of appointing an administrator to take over his diocese.

Campaigners want the Catholic Church to go further however.

Last week, a group of Polish Catholics took out an ad in the Italian newspaper La Repubblica with a personal appeal to Pope Francis in which they claimed that Polish bishops were "hiding cases of paedophilia".

"Rebuild our Church! We are begging you!" the ad said.

Vatican spokesman Matteo Bruni said the pope had been informed and would pray for those who sent the appeal.

"The entire Church must do everything possible so that the canonical norms are applied, cases of abuse are brought to light and those guilty of these serious crimes are punished," the spokesman added.

- 'Always close ranks' -

Justyna Zorn, one of the appeal's organisers, said she was pleased with the quick response.

The group had previously tried in vain to raise awareness through protests, petitions, private letters to the pope and a meeting with the papal ambassador.

"It weighed on me that the hierarchy wasn't doing anything about it... The bishops seemed most concerned with preserving the institution's good image instead of looking after the victims," Zorn told AFP.

She described that mindset as a relic from the communist era when the Catholic Church was frequently attacked and kept under surveillance by the secret police.

"Bishops and priests, even lay Catholics, were taught to never reveal internal church doings, to always close ranks so that what happened in the church, stayed in the church. And that way of thinking continues today."

- 'Evil is being tolerated' - 

The Polish Catholic Church is starting to acknowledge mistakes and says it is taking steps to correct them.

Archbishop Wojciech Polak was last year appointed as its first ever delegate for child protection and he called for an investigation into Janiak after the film was released.

In a rare display of internal division in the hierarchy, Janiak lashed out in a letter to fellow bishops that was leaked to Polish media in which he said Polak had "harmed the image of the Church" by reporting the case.

Father Piotr Studnicki, from the church's child protection office, told AFP that "at least 10 other Polish bishops have been reported for negligence."

Last year, the Polish church said that nearly 400 clergy had sexually abused children over the last three decades.

After two documentaries on the issue by the Sekielskis over the past year, Studnicki said many more victims have come forward, and he now estimates that "that number has at least doubled."

"Either we take an honest approach... or it will simply destroy us," he said, adding: "Not because the issue's being talked about publicly. But simply because evil is being tolerated in our community."