The number of ghost guns appearing in New York City has exploded this year with 131 recovered from Jan. 1 through Wednesday, NYPD statistics show.

That is a staggering 351 percent increase over the 29 recovered by cops during the same period in 2021. The ghost guns made up 12 percent of all guns recovered so far, according to the NYPD.

A ghost gun — a weapon built from a kit that is untraceable — may have been used in Friday’s shooting of three teens, one fatally, outside a Bronx school.

A gun recovered from the home of suspect Jeremiah Ryan is believed to be a Polymer80 ghost gun, sources said.

The Nevada-based retailer sells ghost gun kits on its website and says “we serve citizen, solider, and law enforcement alike” and that “Americans have always, with limited state and municipal exceptions, made their own firearms at home.”

An AR-15 rifle kit goes for $724.99 and parts to make a “Lone Wolf Compact 9mm” pistol were selling for $124.99 on sale, but are now out of stock.

Former Manhattan District Attorney Cyrus Vance Jr. last year called the ghost guns “a significant public safety threat in a way that they weren’t even two years ago.”

Gov. Kathy Hochul in October signed legislation to crack down on ghost guns in New York, including making it illegal to possess an unfinished gun frame or receiver by anyone other than a licensed gunsmith or dealer.