Actress Maggie Kirkpatrick, best known for playing a vicious prison guard who molested vulnerable women, has avoided a prison term for a similar crime.

The 74-year-old showed little reaction in court on Friday when told she would be put on an 18-month community corrections order, including 100 hours of community service, after being found guilty of sexually abusing a mentally unwell teenage girl more than 30 years ago.

She will also have sex offender treatment, be placed on the sex offender registry for eight years, and submit a DNA sample.