The Tasmanian election is to be held on 3 March, with polling suggesting the current Liberal government will struggle to maintain its majority. A hung parliament is likely in the proportional lower house, with the Greens holding a balance of power alongside the major parties – who insist they will only work alone.

Tasmania’s House of Assembly, unique among Australian state lower houses, is elected using the Hare-Clark proportional voting system. There are five electorates – divided the same way as Tasmania’s federal electorates – and each elects five members.

The last election produced a decisive result: the Liberal party won 51% of the primary vote, defeating the incumbent Labor-led government which had governed with the support of Greens members, including as ministers, since the 2010 election. Labor and the Greens suffered a collective swing of over 17%. The Liberal party won 15 seats in the 25-seat chamber: a clear majority.

Recent polling suggests a much closer race this time. While the Liberal party leads Labor in most polls, this is not likely to be enough to win a majority of seats under the Hare-Clark voting system. Only one out of five polls conducted in the last year gave the Liberal party more than 40% of the vote.

The recent polls suggest both Labor and the Greens will gain swings, and the Jacqui Lambie Network may gain a sizeable vote in the northern electorates. It’s hard to see Lambie’s party winning enough votes to win a seat, but it could happen.

Jacqui Lambie’s party could gain a sizeable vote in Tasmania’s northern electorates.

A result that mirrored this polling would likely lead to the Liberal party winning the most seats but falling short of a majority. Such a result would require one of the major parties to form government, either in coalition or as a minority government. Both major party leaders have made various pledges not to govern with the Greens, which would likely make post-election negotiations more difficult.

Labor made a formal alliance with the Greens in both 1989 and 2010, but refused to work with the Greens in 1996, leaving the incumbent Liberal government (with a new premier) to make an informal agreement with the Greens to stay in government.

Pledges not to govern with the Greens do not necessarily rule out any form of minority government, but such a government would likely be less stable and would be vulnerable to defeat in the parliament.

Leader of the Tasmanian Greens Cassy O’Connor (centre) with fellow Greens MPs Andrea Dawkins (left) and Rosalie Woodruff. Photograph: Rob Blakers/AAP

One of the major parties would be given the chance to form a government, with its numbers tested in the parliament. Such a government would be unstable, relying on its opponents to not vote down its budget, and vulnerable to a no-confidence motion. The incumbent Liberal government would likely get the first opportunity to form government.

In the case of a hung parliament, it’s likely the major parties will have a choice: to try and come to an agreement with the Greens to ensure stable government, or take their chances with another election. If a hung parliament does occur, and the major parties stick to their word, another election could come sooner than planned.

The minor-party vote has been increasing across Australia over the last decade, leading to more hung parliaments in every jurisdiction. Tasmania’s voting system makes hung parliaments even more likely, yet the major parties haven’t yet worked out how to deal with these outcomes, instead insisting they will not work with others to form a stable government.

Hung parliaments are not going away. If Tasmania elects one, the major parties won’t be able to ignore the result.