Reeves, 42, whose Buddhist religion is founded on nonviolence, played  a wife-beater in the 2000 film Gift opposite Swank, the Oscar-winning  star of Million Dollar Baby.
 
He said: "By the way, I also learned a bit of ... well, some of the  ladies don't mind it. A part of me was afraid of my violent side.
 
"Once Hilary and I were improvising and I kept saying, 'You're lying.  You're lying'.
 
"The director Sam Raimi said, 'Every time you say, "You're lying,"  instead of saying it, just hit her.' It was very scary."
 
Women's groups in Britain reacted furiously yesterday to his  comments, made to Playboy magazine.
 
Sandra Horley, of domestic violence charity Refuge, said: "It is  irresponsible for Keanu Reeves, a worldwide celebrity, to perpetuate  myths about domestic violence.
 
"Domestic violence kills more 19 to 44-year-old women than any other  cause, including cancer and traffic accidents. With this many women being killed, it is absurd to think that all  these women like violence."
 
The row echoed the uproar which followed 007 star Sean Connery's  interview with the same magazine in 1965.
 
 Connery, who was playing James Bond at the time, said some women  needed to be slapped if they are "a bitch, hysterical or  bloody-minded".