This table shows the percentage of informal votes in Senate elections since 1977.
Prior to 1984, electors were only able to vote below the line. That is, they were required to number every candidate on the ballot paper. Because of the large number of candidates, this resulted in a high informal vote.
Voting above the line was introduced at the elections of 1984. Electors were able to choose to vote above or below the line. A number “1” above the line resulted in the allocation of preferences in accord with tickets lodged with the Australian Electoral Commission by the political parties. The figures shown indicate that above the line voting dramatically reduced the informal vote. Around 95% of electors choose to vote above the line.
Prior to the 2016 election, the Turnbull Coalition government reformed the Senate voting system. Group voting tickets were abolished and optional preferential voting was introduced for above and below the line votes. Voters were advised to vote at least 1-6 above the line and 1-12 below the line. Savings provisions ensured that above the line votes were still formal, even if fewer than 6 groups were numbered.
As in the House of Representatives, a ballot is informal if it does not contain a number “1”, if the voter is identified in any way, or if non-sequential numbering is used. There are a number of exceptions which are set out in Section 270 of the Commonwealth Electoral Act.
|Informal Voting (%) in Senate Elections|
|New South Wales|
|Australian Capital Territory|
Source: Australian Electoral Commission publications