Greens MP Adam Bandt has defied the odds and retained his seat of Melbourne, crushing Labor's hopes of reclaiming the electorate it once owned for more than a century.

In one of the biggest upsets for the Victorian ALP, the Greens deputy leader was on track on Saturday night to beat Labor candidate Cath Bowtell — despite Tony Abbott's attempts to crush the minor party by placing it last on Liberal how-to-vote cards.

Adam Bandt speaks on a live cross from the Greens election event at the People's Market, West Melbourne. Credit:Paul Jeffers

With almost half the votes counted by 9pm, Mr Bandt had almost 44 per cent of first preferences compared to Ms Bowtell, who was polling at around 28 per cent — an anti-Labor swing of almost 12 per cent.

Liberal candidate Sean Armistead had about 21 per cent of primary votes by that stage, but the overall results indicate that many Liberal voters had made up their own minds on who to preference.