The Vatican has given the go-ahead for an investigation into a Polish bishop suspected of covering up sexual abuse of children by clergy -- a subject that has long remained taboo in predominantly Catholic Poland.

The investigation, which was announced on Tuesday by the archdiocese of Poznan, comes just two weeks after the release of a documentary detailing abuse cases that were allegedly covered up by Henryk Janiak, bishop of Kalisz.

The archdiocese said in a statement it had been instructed by the Vatican to conduct an investigation into "the alleged negligence of the bishop of Kalisz in cases of sexual abuse of minors by some clerics".

The film "Hide and Seek", which has been watched by more than seven million people on YouTube, tells the story of two brothers who were victims of abuse by a priest who acted with tacit protection from Janiak.

The Vatican approved an investigation into Bishop Henryk Janiak of Kalisz, Poland, after the release of a documentary detailing abuse cases that he allegedly covered up
The Vatican approved an investigation into Bishop Henryk Janiak of Kalisz, Poland, after the release of a documentary detailing abuse cases that he allegedly covered up GETTY IMAGES NORTH AMERICA / CARL COURT

The documentary is the second in a series by independent journalist Tomasz Sekielski, who has said he will next look into the alleged inaction on abuse of Saint John Paul II, who was pope from 1978 to 2005.

John Paul II, who played a pivotal role in the country's transition from communism to democracy, still commands huge respect in Poland.

Sekielski's first documentary "Tell No One", released in May 2019, has been viewed 23.5 million times on YouTube and has sparked a national discussion of abuse by clergy.

Allegations against senior clergy are rare in Poland -- though an archbishop quit in 2002 after being accused of molesting choirboys.

Poland