A Staten Island captain whose promotion is coming under intense scrutiny by the NYPD sergeants union allegedly threatened to “kill” underlings if they don’t comply with his orders.

In an audio recording provided by a police source Sunday, an irate Capt. Kenneth S. Noonan fumes, “The old culture of the one-two-three precinct is dead — is dead. And anyone who wants to cling to that culture, I’m going to kill at this point, OK?”

The 21-second clip was made during a supervisors meeting around April 2017, when Noonan served as the commanding officer at the Tottenville station house.

Noonan will be promoted this week to deputy inspector — despite being accused by the union of threatening and abusive behavior toward other cops.

Sergeants Benevolent Association head Ed Mullins and a half-dozen cops blasted Noonan’s promotion in an early-morning protest at the 123rd Precinct Sunday.