Throat problems forced Ms Andrews to pull out of the lead role in the Broadway hit musical Victor/Victoria last year. According to reports yesterday, she then elected to have surgery to remove benign nodules in her throat, rather than giving her voice a rest.
But scar tissue on her vocal chords has failed to heal properly and friends say that, while she has regained the ability to speak, she has been warned by doctors to refrain from singing.
Last week Ms Andrews, 62, left New York to spend time at her home in Gstaad, Switzerland. She reportedly hopes that the clean, bracing air of the Alps - setting for her role as Maria von Trapp, the singing nun in The Sound of Music - will help to restore her voice to its former glory.
Her role as the cross-dressing cabaret singer in Victor/Victoria was a long-awaited opportunity to return to Broadway, three decades after she became an international star with The Sound of Music and Mary Poppins, for which she won an Oscar.
The show, created by her husband, film director Blake Edwards, received rave reviews when it opened in 1995.
However, a demanding role and a punishing schedule took their toll, and Ms Andrews missed a number of performances last year because of sore throats, coughs and laryngitis. When she finally withdrew, her part was taken over by Raquel Welch.
Ms Andrews, originally from Surrey, is said to be doing daily throat exercises and to be convinced that she will regain her vocal powers. She reportedly tells friends: "I got through the Blitz and if I could do that, I can get back my singing voice."