Catholic Father Andrea Contin, a parish priest in the northern city of Padua in Veneto, is under police investigation on suspicion of living off immoral earnings and psychological violence.
The 48-year-old also allegedly concealed pornographic home videos in covers bearing the names of various popes.
He is accused of farming out some of his lovers to men on wife-swapping websites, according to The Times.
The priest also allegedly took his female friends for stays at a naturist and swingers resort in Cap d’Agde on the southern French coast.
Complaints were reportedly first made to the local bishop last summer but church authorities did not police, saying they had not yet completed their own investigation.
One 49-year-old church volunteer, who says she had an affair with Father Contin and had sex with him in the rectory, told Il Mattino di Padova: “There were a lot of women hovering around him. I didn’t understand that at first, only later.”
The same news website reported that Father Contin was on holiday in Croatia, where his family visit yearly.
It quoted city mayor Paolo Tonin as saying: “They are also trying to protect him from the clamour of this story that has now gone national.”
Father Contin has not been arrested but a prosecutor was investigating the allegations.