The Puerto Rican star played Maria in the Oscar-winning movie and she feels the actors that portrayed the Hispanic members of the Sharks should never have had to wear makeup to make them appear darker.
"Puerto Rico was colonised by the French, the Dutch and the Spanish and so we are many colours," she tells The Associated Press. "I am one and I really resented it when they put very dark makeup on me because that's not my colour."
"(I) thought the Sharks should have all their own natural colours," she adds. "Some were dark, some were copper skin, some were fair."
Rita reveals she confronted the film's makeup artist over the situation, but he accused her of being racist.
"I remember one time saying to the makeup man who was making me up, 'I really hate this colour because this isn't the colour I am'," she says. "And he actually said to me, 'What, are you racist?'."
"(I was) so stunned that I didn't say anything," she continues. "I didn't know what to say. That's really also how little people know about Puerto Ricans."
Despite her difficulties with how she looked in the 1961 film, the experience wasn't all bad for Moreno, who won an Academy Award for Best Supporting Actress. And she will get to revisit the movie in Steven Spielberg's upcoming remake.
"Never in my wildest dreams did I see myself revisiting this seminal work," a previous statement from Moreno read. "And to be asked by Steven Spielberg to participate is simply thrilling! Then to work together with the brilliant playwright, Tony Kushner - what a glorious stew! I am tingling!".