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Greens Preferences Flow to Labor – 2010 and 2025 Compared
Over the past three decades, the Australian Greens have grown from a collection of state-based parties overshadowed by the centrist Australian Democrats, to being the largest of Australia’s minor parties.
Once minor parties were viewed as bit-players in Australian politics, mere preference conduits for the major parties. Today the Greens are important in their own right electorally, and through elected representation play an important role in Australian Parliaments.
Greens support is now high enough to guarantee the election of a Senator from each state at half-Senate elections. Were it not for party defections, the Greens would have a permanent team of 12 Senators in the 76 seat Senate.
As was highlighted by winning four House seats at the 2022 Federal election, the Greens are now competitive in up to a dozen House seats. Despite being reduced to one House seat in 2025, the Greens remain competitive with Labor and the Coalition.
The Greens won their first general election seat in 2010 on Liberal preferences, and would have won more seats since were it not for the Coalition’s decision since 2013 to put Labor candidates ahead of the Greens on how-to-vote preference recommendations.
In this post I’m comparing two elections 15 years apart, 2010 and 2025, and examining how support for the Greens and the party’s preference flows have changed.
The 2010 election was the first where the Greens passed 10% of the vote. Led by Bob Brown, the Greens were still seen largely as an environment party, and Brown helped Labor and Julia Gillard form government after the election. Adam Bandt won the electorate of Melbourne in 2010, coming from behind to win after receiving three-quarters of Liberal preferences.
As Greens leader at the 2025 election, Adam Bandt lost his seat at an election where the Greens vote was roughly the same as in 2010. But 15 years had seen the development of differences in the geographic pattern of Greens support, and an increase in preference flows to Labor.
### Past Performances
The registration in the early 1980s of a party called the Greens by members of a socialist party delayed the state-based Greens parties becoming a national force until the mid-1990s. It was not until the 2004 election that all state Greens branches came under the umbrella of the Australian Greens.
Combining the pre-2004 parties into a single total, the chart below shows national vote for the Greens since 1996. The 1996 election was the first where the party contested more than 100 House seats. 2001 was the first election where the Greens contested every seat, and the Greens were boosted by their strong opposition to the Howard government’s actions to stop illegal boat arrivals. After nudging 5% for the first time in 2001, support for the Greens rose further after 2004 with the electoral demise of the Australian Democrats.
2010 was the first election where the Greens polled above 10%. Support slipped on the election of the Abbott government in 2013, but has been above 10% at the four elections since 2016. The chart below shows the party’s primary vote percent since 1996 plus the party’s total percentage preference flows to Labor at each election.
While the political importance of the Greens these days is more than just the party’s preference, I believe the continuing climb in preference flows to Labor election after election tells you something about the party’s support base.
The Greens have been consistently demonised and denied preferences by the Coalition since 2013, and I think the result is fewer Coalition voters being prepared to put the Greens first before giving a preference back to the Coalition. Greens voters giving preferences to the Coalition have fallen from 21.2% in 2010 to just 11.8% in 2025. I’ll go into how this has changed on a seat by seat basis later in this post.
Three decades ago it was common for the Greens to get publicity by talking up preference ‘deals’, especially in stressing to Labor how much more important Green House preferences were compared to the Australian Democrats when it came time to negotiate Senate preferences.
The 2010 election was the last where the Greens issued numerous open how-to-votes. There were 44 seats in 2010 where the Greens did not recommend preferences to Labor. In an article I published back in 2011, I estimated that open how-to-votes lowered the flow of Green preferences to Labor by about 3%.
Green preference now flow to Labor at a rate that the Liberal and National parties struggle to achieve between each other in three-cornered contests. In reverse, Labor preferences to the Greens where counted are often about 10% weaker in flow.
Every finding I’ve teased out of the small sample of data on how-to-vote follow rates shows that most voters do not simply copy how-to-votes. For minor parties, it is having a clear message that builds preference flows. For both the Greens and One Nation, recent elections have seen consistent messaging about which major party they are closer to and which they oppose. And in that time both parties have seen stronger preference flows develop.
A case in point for the Greens is the message below from the party’s 2025 campaign site. The simple message to keep Peter Dutton out drove the party’s support and I believe also drove up the party’s preference flows to Labor.
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### Support by Electorate
What drove me to write this post was a suspicion that there had been a change in the geographic pattern of Green support, the party’s overall support static but rising and falling in a small number of seats.
The chart below is a simple frequency distribution comparing Green support by electorate at the 2010 and 2025 elections.
The two charts are roughly similar in distribution, except there is a decline in the number of electorates where the Greens poll 15-20%, and an increase in seats greater than 20%.
When you dig down into the data, in the seven urban seats won by Independents of a ‘teal’ hue in 2025, the Greens polled 7.8% compared to more than double at 17.0% in 2010. That looks like another example of strategic voting to me, Greens supporters switching to support the candidate most likely to defeat the Liberal, or perhaps more likely than a Green to have an impact on environment policy.
The seats where Green support has risen most are gentrified former Labor inner-city seats where Liberal candidates now finish third and the real contest is between Labor and the Greens.
### Preference Flows to Labor by Electorate
The frequency distribution chart below plots preference flow distributions for the 2010 and 2025 elections. Excuse the pun, but it shows graphically how preference flows to Labor increased between 2010 and 2025.
In 2010 there were 95 divisions where Green preferences to Labor were less than 80%, but only 10 in 2025.
In 2010 there were no divisions where Green preferences passed 90% compared to 45 divisions in 2025.
At every election there are some ‘random’ first preferences for a party, which is why flows never reach 100%. As Greens support has risen, the number of randoms as a proportion of the Green vote has diminished. And the hardening of Coalition opposition to the Greens, and vice versa, has driven up the flow of Green preferences to Labor.
Interestingly, in the small number of seats where Labor preferences are distributed in Liberal-Greens contests, the flow of Labor preferences to the Greens is generally weaker by about 10% than than reverse preference flows.
### Green Percentage Votes by Electorate versus Preference Flows
The two scatter charts below plot Green primary vote support and preferences to Labor against each other. Comparing the two charts again shows the rise in Green preferences to Labor.
The 2010 chart has no points above 25% because data for Batman, Grayndler and Melbourne are not available. As the trend line through the data suggests, there was a wider variance in results by electorate. The trend line shows that the starting point for Green preference flows was 70%.
The 2025 chart shows many more points above 25% of the primary vote, and the points in the chart have shifted upwards compared to the 2010 chart. The starting point for Green preferences from the trend line is 80%.
The variability from seat to seat is smaller for the 2025 data, but that’s because the overall rate of Green preferences to Labor has risen. As a preference flow can’t go above 100%, a rise in the base rate of preference flows must diminish the variability between individual electorates.
### A Final Comment
The strength of Green preferences to Labor in 2025 is astonishing. The preferences flow at rates that used to be seen between the Coalition parties in the days when the two parties used to compete against each other. And where the two Coalition parties used to compete only at the electoral level, Labor and the Greens are in contest both locally and in the broader campaign against the country. Animosity between the two parties seem not to impact Green preferences.
Preferential voting was introduced more than a century ago to allow the two conservative parties to compete against each other in seats without splitting the conservative vote and delivering victory to Labor.
The boot is on the other foot these days with preferential voting allowing Labor and the Greens to compete against each other without delivering seats to the Coalition.
Preferential voting produces more candidates on the ballot paper from a range of competing political positions, without a candidate’s mere presence necessarily changing the result.
As a prime example of what can happen when you don’t have preferences, see the result in former UK Prime Minister Liz Truss’ seat at the 2024 UK election.
I very much doubt UK Labour would have won that seat under preferential voting. The Twitterati who are chirping about Labor winning the 2025 election with only 34.6% of the first preference vote continue to willfully ignore why we have preferential voting.
Given the rise of One Nation in recent opinion polls, I can’t imagine the Coalition will be any keener on getting rid of preferential voting than Labor.
