She has also made guest appearances on the NRL Footy Show on Network Nine. Duncan married actor John Orcsik in June 1982 after they met acting together in Cop Shop. They subsequently divorced. They have since worked together, including acting together in Paradise Beach.
Her numerous television roles include playing Nurse Lisa Brooks in The Young Doctors (1976–77), Detective Danni Francis in Cop Shop (1977–83), for which she twice won the Logie Award for Most Popular Actress, Lorelei Wilkinson in Prisoner (1986), Janet Bryant in Richmond Hill (1988) and Bridget Jackson in Home and Away