Maria Franziska von Trapp, the last survivor of the Austrian musical family whose escape from the Nazis was immortalised in The Sound of Music has died.

Ms Von Trapp, 99, died at her home in the northeastern US state of Vermont on Tuesday of natural causes, Johannes von Trapp told CNN.

She was one of the original members of the Trapp Family Singers group.

Maria Franziska was the third of seven Austrian-born children of Captain Georg von Trapp and his first wife, Agathe Whitehead.

The captain's second wife, Maria Kutschera von Trapp - famously portrayed by Julie Andrews in the 1965 movie The Sound of Music - wrote a book about the family.

It served as a basis for two movies in German, a Broadway production and the hit Hollywood film.

The family patriarch, portrayed in the movie by Canadian actor Christopher Plummer, had three children with his second wife: Rosmarie, Eleonore and Johannes.

The family fled Nazi-occupied Austria in 1938, moved to the US the following year, and settled in Vermont in 1942, where they opened a resort called the Trapp Family Lodge.

They gave their final US concert in 1956, according to the lodge's website.

Ms Von Trapp served as a lay missionary in Papua New Guinea, while her half brother Johannes is president of the Trapp Family Lodge.

"Thank you for your thoughts. Maria had a wonderful life and while we will miss her, the memories of her will live on," Mr Von Trapp said in a statement.

The Sound of Music won five Academy Awards and is one of the highest-grossing Hollywood movies of all time.