2016 Australian Senate election

The 2016 Australian federal election in the Senate was part of a double dissolution election held on Saturday 2 July to elect all 226 members of the 45th Parliament of Australia, after an extended eight-week official campaign period. It was the first double dissolution election since the 1987 election and the first under a new voting system for the Senate that replaced group voting tickets with optional preferential voting.

The final outcome in the 76-seat Australian Senate took over four weeks to complete despite significant voting changes. Earlier in 2016, legislation changed the Senate voting system from a full-preference single transferable vote with group voting tickets to an optional-preferential single transferable vote.^[1] The final Senate result was announced on 4 August: Liberal/National Coalition 30 seats (−3), Labor 26 seats (+1), Greens 9 seats (−1), One Nation 4 seats (+4) and Nick Xenophon Team 3 seats (+2). Former broadcaster and founder of the Justice Party Derryn Hinch, won a seat, while Jacqui Lambie, Liberal Democrat David Leyonhjelm and Family First's Bob Day retained their seats. The number of crossbenchers increased by two to a record 20. The Liberal/National Coalition will require at least nine additional votes to reach a Senate majority, an increase of three.^[2][3][4]

A number of initially-elected senators were declared ineligible a result of the 2017–18 Australian parliamentary eligibility crisis, and replaced after recounts.

The two major parties negotiated to allocate a six-year term to the first elected six of twelve senators in each state, while the last six received a three-year term. This was consistent with the Senate practice on all seven previous occasions.^[5] In 1983 the Joint Select Committee on Electoral Reform had unanimously recommended an alternative "recount" method to reflect proportional representation,^[6] and the Commonwealth Electoral Act provides for a recount on that basis.^[7] This alternative method had been supported by both Labor and the Coalition in two separate, identical, bipartisan senate resolutions, passed in 1998 and 2010.^[8][5][9] By not adhering to their previous resolutions, Labor and the Coalition each gained one senate seat from 2019.^{[10][11][12][13][14][15]}

The final Senate result was announced on 4 August. The incumbent Liberal/National Coalition government won 30 seats, a net loss of three − the Coalition lost four Senators, one each from New South Wales, Queensland, Western Australia and South Australia, but gained a Senator in Victoria. The Labor opposition won 26 seats, a gain of one − a Senator in Western Australia. The number of crossbenchers increased by two to a record 20. The Liberal/National Coalition would require at least nine additional votes to reach a Senate majority, an increase of three.^{[2][3][4][16]}