Terms and Conditions: https://www.portrait.gov.au/ssl/nppp/terms.php
The National Portrait Gallery invites all Australian residents to enter the inaugural National Photographic Portrait Prize 2007 which will be displayed in the Gallery from 6 December 2007 to 23 March 2008. The Prize, sponsored by Visa International, is an annual event intended to promote the very best in contemporary photographic portraiture by both professional and aspiring Australian photographers.
With the generous support of Visa International, the National Portrait Gallery is offering a prize of $25,000 for the most outstanding photographic portrait. A selection panel of three judges will make an initial selection from all entries to determine the shortlist of finalists for inclusion in the exhibition. Unsuccessful applicants will be notified by letter at this time. The judges will choose the prize winner from the portraits on display in the exhibition. Entries will be judged on their power as a portrait photograph rather than the status of the sitter or the reputation of the photographer.
Also:
The entry must be a portrait in the broadest sense that is an image of an individual person or persons. The photograph must be taken by the entrant from life. The subject of the portrait can be anyone. Group portraits and self portraits will be accepted. The portrait must employ a photographic medium - ie. an image created by using either traditional photographic emulsion or digital process.
... so I'm guessing a fair bit of PP-ing latitude is extended to participants.
Other details: $25 entry fee, submission for judging by email but you have to deliver it to them framed if you're chosen, and pick it up afterwards at your expense.
Oh, and:
Copyright in all the photographs exhibited will remain with the artist. It is a condition of entry however that entrants grant the National Portrait Gallery the right to freely use and reproduce all exhibited works for publicity, promotional and educational purposes associated with the Prize in both digital and print mediums.
Might be worth a go?