Multiple voting - Immediately after each federal election the AEC scans large volumes of voter lists and follows up every case where a voter is marked off more than once.
After careful assessment, instances of multiple marks are distilled to the cases where the AEC cannot reasonably exclude the possibility that multiple voting has occurred. These matters are then for the AFP and the CDPP to consider - the AEC has no authority to prosecute multiple voting in a court of law.
In close seats, the AEC prioritises its examination of multiple voting in the post-election period to ensure that an election result is safe. Recourse exists if ever the number of multiple votes exceeded the winning margin in a seat. Further information about multiple voting issues.