Informal voting in Australia is a sometimes controversial aspect of the electoral system. Rules differ between the House of Representatives and the Senate, sometimes causing confusion.
House of Representatives
- Informal Voting Statistics – 1983-2013 – table showing the national and state-by-state informal voting percentages at every federal election since 1983
- Analysis of 2004 Federal Election Informal Votes – AEC Research Paper (PDF)
- Analysis of 2004 Informal Votes – Seat-by-seat – AEC Research Paper (PDF)
- Categories of Informal Voting 1987 – an interesting set of statistics showing how informal voters spoiled their ballot papers.