The new $100 banknote has a range of new security features designed to keep the banknote secure from counterfeiting. The security features are similar to those on the $5, $10, $20 and $50 issued between 2016 and 2019.

Each denomination in the new series of banknotes will feature a different species of Australian wattle and a native bird within a number of the security features. The $100 banknote features the Acacia pycnantha and the Australian Masked Owl (Tyto novaehollandiae).

The $100 banknote retains the portraits of Sir John Monash and Dame Nellie Melba, which are drawn from the same source photographs represented on the first polymer $100 banknote.

The banknote celebrates the contributions of these two outstanding Australians. Sir John Monash was an engineer, soldier and civic leader. He was a significant figure in the building-construction industry. Monash is also widely recognised for his service as a commander in the First World War. Dame Nellie Melba was an internationally renowned soprano who performed in Australia, Europe and the United States of America in the late 19th and early 20th century. In addition to performing, Melba made important contributions to the arts through teaching at the Melba Memorial Conservatorium of Music, now the Melba Opera Trust, in her home town of Melbourne.

Monash was acknowledged as one of Australia's foremost experts in reinforced concrete for civil construction projects.

• In 1926 Melba published her own singing tutorial the Melba Method and was the first Australian to appear on the cover of Time magazine in 1927.

• The microprint on the new $100 features excerpts from Melba's autobiography Melodies and Memories and a letter written by Monash.