Prime Minister's wife Rosmah Mansor should take legal action against the United States Department of Justice if she feels she has been slandered, said former premier Dr Mahathir Mohamad.

The Parti Pribumi Bersatu Malaysia chairperson said this after Rosmah's lawyer issued a statement warning publications and social media users of the risk of legal action if Rosmah is slandered.

"I heard Rosmah will sue whoever who accuses her in relation to the jewellery mentioned in the filing by the United States Department of Justice...