Her agent said she died on Friday afternoon in hospital after surgery for a fall she had earlier in the week.
Madoc was probably best known for her role as Gladys in the Croft and Perry sitcom Hi de Hi, one of the lead roles, for which she received a BAFTA TV award nomination for Best Light Entertainment Performance.
In 1971 Ruth Madoc played Fruma Sarah in the film version of the musical Fiddler on the Roof, and in 1972 she appeared as Mrs Dai Bread Two in the film of Under Milk Wood. She also appeared regularly in the entertainment programme Poems and Pints on BBC Wales.
She provided one of the alien voices in the Cadbury’s Smash commercials in the 1970s, and made a brief appearance in the 1977 film, The Prince and the Pauper (aka Crossed Swords).
Madoc is survived by her son Rhys and daughter Lowri from her first marriage to her first husband Philip Madoc.
In 1982 she married her second husband John Jackson.