Outraged parishioners have abandoned a Manhattan Lutheran church – after their pastor vowed to keep a convicted kiddie-porn collector on staff.

“The families were horrified,” said Brooklyn Criminal Court Judge John Wilson, who attended St. Peter’s Church at the Citicorp Center in Midtown with his wife and young son until learning last October that its receptionist was a registered sex offender. “It’s truly disappointing that someone in a position of authority would think so little of protecting children.”

But the Rev. Amandus Derr said that by keeping William Prante on the job, the church is fulfilling its Christian mission of rehabilitating sinners, while protecting kids by barring Prante from being alone in St. Peter’s with anyone else.

Prante, however, regularly sees children at the church as part of his job.

Prante, 61, pleaded guilty in 2004 to a Louisiana child-porn charge after authorities found more than 700 sexually explicit images of children, including girls who appeared younger than age 5, at his home.

Prante, who downloaded the porn onto his work computer during his past job as an arts group’s education director, served two years in prison.

“The best day of my life was the day of my arrest because I could get healthy,” Prante told The Post yesterday.

After his release, he moved to New York – registering as a low-risk sex offender – and started hanging around St. Peter’s, where a friend is the organist.

But when the church finance director – who was unaware of Prante’s crime – hired him last year, a parish council member uncovered news stories about him and complained to church officials before ultimately resigning.

Derr then felt compelled to tell his congregation, and did so following a Sunday service with Prante’s permission.

“That day was particularly heinous,” said a parishioner and mother of a young child, one of more than a dozen congregants who stopped attending St. Peter’s afterward.

---