Pop star Ricky Martin faces fresh accusations of sexual assault, days after he sued his nephew for extortion over similar allegations.

The Grammy Award Winner was named in a second complaint filed on Friday in Martin’s home of San Juan, Puerto Rico the Associated Press report.

Martin, 50, said he was taking legal action against his nephew last week, suing Dennis Sanchez Martin for $US20 million ($29 million) in damages to his reputation after the singer was accused of sexual assault.

AP reports Martin’s nephew also made the new accusations.

Martin’s lawyer José Andréu-Fuentes denied the allegations, telling People the claims were “wildly offensive and completely untethered from reality”.

“When this man previously made similar allegations, his legal case had to be withdrawn – not least because he himself admitted under oath that Ricky Martin had never assaulted him in any way,” he said in a statement.

“Now, after being sued for trying to extort Mr Martin, he is attempting to spread his lies again.”

Martin’s nephew filed a sexual assault lawsuit against the singer and asked for a restraining order in early July.

Martin’s representative told People magazine at the time they believed their client would be fully vindicated when the “true facts come out”.

In late July, the case was withdrawn by the nephew and a judge dismissed a temporary restraining order placed against the Livin’ La Vida Loca singer, after Mr Sanchez Martin admitted under oath that he had never been sexually assaulted by his uncle.

Martin did not publicly address the incest accusations until after the matter was dismissed.

He said in a video statement that the weeks of allegations were “devastating” for him and his family and that he had been unable to defend himself publicly.

“I’m in front of the cameras today because I really need to talk in order for me to start my healing process,” Martin said in the video.

“For two weeks, I was not allowed to defend myself because I was following a procedure where the law obligated me not to talk until I was in front of the judge.”

“But I’m going to tell you the truth. It has been so painful. It has been devastating for me, for my family, for my friends. I don’t wish this upon anybody.