A Long Island town clerk was arrested yesterday after he allegedly tried to cover up a sexual-harassment suit by blackmailing his accuser with dirty photos of her, law-enforcement sources said.

Mark Bonilla, 50, was accused of sexual harassment by a female employee of the Town of Hempstead Clerk’s Office. In August, he allegedly approached a male employee, Alex Desidoro, who had been intimate with his accuser and tried to get lurid pictures of her.

The married Bonilla told Desidoro he would be promoted if he handed over the steamy pics, the criminal complaint states.

“Bonilla used his official position to attempt to gain possession of compromising photographs of his accuser in an attempt to silence her and discredit her claim,” a law-enforcement source said.

Hempstead Town Supervisor Kate Murray called on Bonilla to resign.

Bonilla has been charged with official misconduct, attempted coercion, and petit larceny.