Mr. Westwick has vehemently denied each of the accusations on social media. His publicist could not immediately be reached for comment.
Kristina Cohen, the first of the two women to come forward, said on Facebook on Monday that Mr. Westwick had raped her three years ago while she was dating a friend of his who was a producer.
“It was a nightmare, and the days following weren’t any better,” she wrote. “The producer put the blame on me, telling me I was an active participant. Telling me that I can’t say anything because Ed will have people come after me, destroy me, and that I could forget about an acting career.”
The Los Angeles Police Department began investigating the accusation after Ms. Cohen filed a police report on Tuesday that named Mr. Westwick, said Officer Drake Madison, a spokesman for the department.
“I have never forced myself in any manner, on any woman,” he added. “I certainly have never committed rape.”
Mr. Westwick denied the allegations on Thursday, and said it was “disheartening and sad” that people would suggest he “had anything to do with such vile and horrific conduct.”
He added: “I have absolutely not, and I am cooperating with the authorities so that they can clear my name as soon as possible.”