A historic Manhattan church is an unholy mess, unable to rebuild its fire-ravaged sanctuary because an insurance company shorted it by tens of millions of dollars, according to a lawsuit.

St. Sava Serbian Orthodox Church says the cost to rebuild is $60 million, according to court papers accusing insurer Church Mutual of negligence.

The insurance company sold St. Sava policies estimating the cathedral would take just $12.7 million to resurrect, the church claims.

The May 1, 2016, inferno at the West 25th Street house of worship began after a caretaker left candles burning, authorities concluded.

The 160-year-old church cannot rebuild because of Church Mutual’s “woefully inadequate” payout, which left it $47 million short, according to the legal claim.

The church says the insurer arrived at its drastically reduced figure because it simply added the original 1945 purchase price — $10 million — to the cost of later improvements, without ever actually considering the cost of modern-day expenses.

St. Sava is seeking at least $47 million in damages.

Church Mutual declined to comment.