Marzilli, 50, was scheduled to be arraigned in Lowell District Court on Wednesday.
Corey Welford, a spokesman for Middlesex District Attorney Gerry Leone, said Marzilli is accused of approaching a woman who was sitting on a park bench, making an "inappropriate comment" and attempting to touch her in a sexual manner, which she forcibly resisted.
Welford said when Marzilli was approached by Lowell police he allegedly gave them a false name. He was arrested after a police chase.
Marzilli's lawyer, Terrence Kennedy, told reporters Tuesday night as Marzilli was released on $1,500 cash bail that his client "completely and totally denies" the allegations, which he called "ridiculous."
A call to Marzilli's home was not returned.
Senate President Therese Murray said in a written statement that she was troubled by Marzilli's arrest. "These are troubling allegations, and we take them very seriously. We will pay close attention to this matter as it develops," she said.
Last month authorities declined to charge Marzilli after a woman claimed that he had touched her inappropriately, saying there was insufficient evidence. That investigation stemmed from an incident on April 6, where a woman told Arlington police that Marzilli had assaulted her.
Leone said investigators interviewed the woman and additional witnesses multiple times, including people who had seen both the woman and Marzilli at a fundraiser earlier that night.
Marzilli, a Democrat, spent 17 years in the House before winning a special election in December to fill a vacant seat in the Senate.