The ex-head of Belgium's Catholic Church has lodged a breach of confidentiality complaint after a police probe leak saw him wrongly linked in the press to a photograph of a young naked girl.

Cardinal Godfried Danneels, who is being investigated by police over allegations he shielded predator priests, objected to a report by the Flemish newspaper Het Nieuwsblad about a photo of a young naked girl found on his computer.

The public prosecutor's office confirmed earlier Thursday that the image was in fact an innocent one from the website of the Flemish public television channel VRT.

"The photo had been automatically downloaded onto the computer of Cardinal Danneels from the VRT website without any action by him," said his spokesman Hans Geybels.

"The insinuations... are completely baseless. The news of this photo found on the computer of the cardinal was taken up and commented on not only by the national press, but also the international press," Geybels said.

"The reputation of the cardinal was therefore once more tarnished in an irreparable way."

The cardinal was on Tuesday questioned for over 10 hours.

Danneels, 77, denies accusations by a retired priest that he shielded sexual predators in the clergy when he headed the country's Catholic Church from 1979 to 2009.

Late last month, police raided the Church's headquarters, seized computer files from Danneels's home and even searched a cathedral crypt in an operation that angered the Vatican.

Paedophile priest scandals and allegations of high-level cover-ups have surged this year across Europe, the United States and Brazil.