A SELECTIVE high school teacher allegedly took girl students to sex clubs, nude beaches and had sex with a number of them, aged 13 to 19.

Sean Shaynak, a divorced 44-year-old father of a nine-year-old daughter, faces 36 charges of kidnapping and criminal sexual acts on the school girls where he taught — the prestigious Brooklyn Technical High School in New York, the New York Post reported.

New York Mayor Bill de Blasio’s son Dante attends the school.

Shaynak, who was initially charged last month with four counts of sending pictures of his penis to female students, is also accused of giving some of his victims perfect scores on their schoolwork.

Brooklyn Assistant District Attorney Joseph Mancino said once investigators looked through his computers and phones, they found clues that Shaynak had been in sexual relationships with multiple female pupils. He was rearrested on Tuesday.

“From the additional case, we identified six additional victims,” Mancino said in court.

“The defendant clearly looked to groom these students.”

Shaynak’s forehead was dotted with perspiration and a bead of sweat ran down his left temple as he sat in handcuffs awaiting his arraignment.

Prosecutors described a four-month-long sexual relationship Shaynak had with another Brooklyn Tech student.

“He brought her to a sex club out of state where he performed sex acts on other people and other people performed sex acts on him in the presence of the victim,” Mancino said, adding that Shaynak bought her cigarettes and took her on a terrifying car ride during which he screamed that she couldn’t tell her parents.

Shaynak also took one teenage girl to a New Jersey nude beach, gave her “Jack Daniels and tequila to the point where she passed out” at his house, and traded over 10,000 text messages with her, Mancino said.

The science teacher even gave good grades to at least some of the girls he was abusing.

“He would routinely give her 100s in his class even though she turned in work with no answers,” Mancino said of a Brooklyn Tech student whom Shaynak had sex with and also raped.

Shaynak pleaded not guilty at his Brooklyn Supreme Court appearance.

“One of them was routinely contacting him, and that might explain the voluminous text messages,” defence attorney Kim Summers said in an attempt to explain the 10,000 text messages.

Judge Martin Murphy increased Shaynak’s bail from $25,000 to a total of $1 million on all charges. He had been a teacher at the prestigious school since 2012.

“It is shocking that a public high school teacher allegedly sexually preyed on vulnerable students. We will now seek to vindicate the rights of those students,” Brooklyn District Attorney Ken Thompson said in a press release.