An NYPD traffic-enforcement agent used a gun to coerce at least two women into oral sex by threatening to arrest them, police said Monday.

Isaiah Delvalle, 27, of East New York, Brooklyn, was off-duty when he flashed the illegal gun and told his victims, who are believed to be prostitutes, that he would lock them up if they didn’t comply, authorities said.

One victim turned over a semen sample to police, and an officer later snagged a matching DNA sample from a straw Delvalle used at a restaurant, court papers say.

Delvalle was arrested outside his house Friday. He was released on bail Saturday.