Bill Cosby has filed a motion to dismiss a defamation lawsuit hanging over him as he continues to battle sexual assault and inappropriate behaviour accusations from over 20 women.

The comedian's attorneys submitted the motion on Friday (27Feb15) as they suggested they would earlier this week (beg23Feb15).

Tamara Green filed suit against Cosby at the end of 2014 and she was joined by Therese Serignese and Linda Traitz at the beginning of 2015. The three women claimed the comic and his legal team had defamed them by calling them liars when they accused Cosby of drugging and sexually assaulting them in the 1970s.

His lawyers' motion reads: "The law does not require that one stand idly by while he is publicly attacked. Instead the law entitles an individual who is accused of serious wrongdoing to rebut the allegations without facing defamation claims.

"This lawsuit is, rather, a misuse of the law of defamation to attempt an end run around the relevant statutes of limitations for the alleged assaults."

When Serignese and Traitz joined the suit in January (15), Green's attorney, Joe Cammarata, said, "We certainly welcome other people standing up to Bill Cosby to redress harm caused to them by statements made by Mr. Cosby through his lawyer and spokespeople."

The three women have until 20 March (15) to file a reply to the motion for dismissal.