In a small number of House of Representatives seats, it can be difficult to determine which candidates to select for the initial two-candidate preferred (TCP) count. This can happen in seats where it is a tight three-way contest or in other seats where it is just difficult to predict who will be second or third.

In these cases, the AEC may conduct a three-candidate preferred count – sorting votes into piles for three candidates instead of two. This is an administrative process that is not open to challenge by scrutineers, but may be observed.

In a three-candidate preferred (3CP) count we set aside ballot papers with 1st preferences for the three leading candidates, then we take ballot papers with 1st preferences for the remaining candidates and allocate each ballot paper to one of the three leading candidates based on the 2nd preference on that ballot paper (or the next preference available for one of the three leading candidates). We then tally up how many votes each of the three leading candidates has to understand who the top two candidates will be.

In all 150 divisions, the AEC will conduct a full distribution of preferences in which the lowest placed candidates are excluded and their preferences distributed until the final two candidates are known. The choice of TCP candidates and the results of 3CP counts have no bearing on the result of the distribution of preferences.