A Midtown church slated to close as part of a massive shakeup by the Archdiocese of New York is a veritable art museum filled with dozens of stunning murals painted by a world-renowned artist — and parishioners fear the treasured works could be lost forever.

Our Lady of the Scapular and St. Stephen Roman Catholic Church in Kips Bay is adorned with 45 works by Constantino Brumidi, who spent years working to capture the essence of Christ in the more-than-150-year-old church.

“They are absolutely wonderful,” said the church’s pastor, the Rev. Robert Robbins. “It’s really sad.”

The Italian-born painter is most famed for his murals painted in the dome of the Capitol Building in Washington, DC.

St. Stephen’s collection includes the largest Brumidi painting in the world, said Robbins — a towering mural above the altar that depicts Christ’s crucifixion.

And Christ’s final hours are depicted in in the Stations of the Cross a series of detailed Brumidi paintings that surround worshippers along the church’s walls.

The Archdiocese of New York — which spans three boroughs and several upstate counties — announced this week that it will restructure 112 of its 368 parishes by merging many together and closing down 31 churches completely.

Robbins said he will be taking over three parishes that will merge into a nearby church next year after St. Stephen’s closes along with 30 others throughout the archdiocese, which spans three boroughs and several upstate counties.

“The history of that church goes back to 1848,” he said, adding the church had the largest parish in the United States just before the turn of the 20th century.

But like so many other Catholic churches in New York, attendance has been dwindling, and the Church has been financing seven years’ worth of structural repairs to St. Stephen’s to the tune of $2 million.

“On a Sunday, there would be 20,000 people at the church,” he said, referring to the church’s glory days. “To go from 20,000 down to a couple of hundred breaks your heart.”

Robbins said archdiocese leader Timothy Cardinal Dolan has promised that all religious artworks at the 31 churches set to close next year will be saved.

“They have to decide what to do with the building before you can take anything out of it,” Robbins said.

“They will not be put out in the garbage.”

But parishioners are worried the massive collection of frescos will be split up or sold off when the church closes down next year.

“They’re just so angelic and so colorful and so beautiful,” said Joseph Sullivan, a parishioner of almost 25 years. “They reek of history and spirituality.”

“I’m afraid of what will happen to all that treasured art.”

The Archdiocese of New York announced this week it intends to restructure 112 out of its 368 parishes by merging many together and closing others down completely.