“A short time ago I called the Labor candidate for Melbourne Sarah Witty to concede, to congratulate her and to wish her all the best as the next member for Melbourne,” Bandt said.

“The Greens got the highest vote in Melbourne but One Nation and Liberal preferences will get Labor over the line.”

Voting preferences and recent boundary changes in the electorate contributed to an insurmountable “Everest” for the Greens, Bandt said.

“To win in Melbourne, we needed to overcome Liberal, Labor and One Nation combined and it’s an Everest we’ve climbed a few times now, but this time we fell just short,” he said.

Recent boundary changes meant the electorate lost left-leaning voters in the north to Wills, and gained typical Labor voters to the south, in South Yarra and Prahran.

“A lot of new people south of the river were moved in, people who we didn’t have a huge amount of time with to make such a deep connection with and this made the margin much, much tighter,” Bandt said.

The Greens leader since 2020 and Melbourne MP since 2010, Bandt thanked voters for conveying a “message of hope” during national issues such as the marriage equality plebiscite and the Voice referendum, where the electorate recorded the highest votes of support in the country.

“I want to thank Melbourne voters for regularly giving me the highest vote, including in this election, and to thank you for the last 15 years and the chance to do some amazing things together,” he said.

The opposition leader’s unsuccessful campaign may have helped Labor close the deal in Melbourne, Bandt said.

“That huge rip tide from Liberal to Labor had an effect on us as well,” he said.

“People in Melbourne hate Peter Dutton, and with very good reason.

“My initial take is that some votes leaked away from us to Labor as people saw Labor as the best option to stop Dutton.”

The Greens have also conceded defeat in Brisbane and Griffith, while Elizabeth Watson-Brown looks set to retain Ryan.

The former lawyer was the first to turn an electorate Green in the lower house when he won the inner-northern Melbourne seat from Labor in 2010.

He was successfully re-elected at the next four elections, winning the 2022 vote count with a 6.5 per cent margin.

Bandt will exit parliament with the Greens holding the balance of power in the Senate.

“It has been a joy to represent you and I hope I’ve made you proud,” he said.

“I’m really proud of what I’ve achieved as a leader.”

The unseating of Bandt has left the Australian Greens leaderless.

A new leader will be voted on in a party room meeting next week.

Until then, Greens senator Nick McKim will act as caretaker for the party.

Senators Mehreen Faruqi and Sarah Hanson-Young are considered the frontrunners for the role.