She earned the nickname "Big Mel," having made several newspaper headlines in London as one of the largest babies born in Britain, at 11 pounds, 9 ounces.
She worked professionally as a child actress and later as an adult, when she was sometimes billed by her married name Melanie Morse MacQuarrie.
Her film work includes roles in Prom Night (1980) with Jamie Lee Curtis and Leslie Nielsen, as well as Murder by Phone (1982) with Richard Chamberlain.
Her TV appearances include Noises in the Nursery, Drought, and the popular Canadian television series Street Legal.
She was survived by her husband, Donald, and two daughters, Vanessa Root Archer and Megan MacQuarrie, as well as her father and younger brother.