Hollywood's widening sexual harassment crisis has ensnared Oscar-winner Dustin Hoffman and prominent film director Brett Ratner.

Six women have accused Brett Ratner of sexual misconduct in a Los Angeles Times report while Hoffman has apologised for allegedly sexually harassing a 17-year- old intern in 1985.

Writer Anna Graham Hunter alleged in a Wednesday column in The Hollywood Reporter that the now 80-year-old Hoffman groped her on the set of TV movie Death of a Salesman and "talked about sex to me and in front of me."

Hoffman issued a statement on Wednesday, apologising for "anything I might have done could have put her in an uncomfortable situation. I am sorry. It is not reflective of who I am."

Actress Olivia Munn, meanwhile, alleged that while visiting the set of Ratner's After the Sunset in 2004, he masturbated in front of her in his trailer.

Ratner's lawyer issued a statement in which he said the director "vehemently denies the outrageous derogatory allegations" and is "confident that his name will be cleared once the current media frenzy dies down and people can objectively evaluate the nature of these claims."

Ratner and Hoffman are the latest Hollywood figures to face allegations of misusing their power to harass actresses, a list that now includes producer Harvey Weinstein and writer-director James Toback. Harassment allegations have also been levied against actors Kevin Spacey and Jeremy Piven.

Police in Beverly Hills have announced they have launched criminal investigations over complaints received about Weinstein and Toback.

Weinstein also is being investigated for sexual assault or rape by police in Los Angeles, New York and London.

Weinstein has denied engaging in any non-consensual sexual contact.

- AP