In a line they touted prominently before winning their roles on Wednesday, Senator Shoebridge and his deputy, fellow upper house member Steph Hodgins-May, have vowed to replace Labor, rather than try to reform it.
Environment Minister Murray Watt said the pledge was a sign Senator Shoebridge was "one of the leaders of the angry, militant faction of the Greens Party" and urged him to work collaboratively with the government.
"We certainly hope that Senator Shoebridge can take a more constructive approach to working with the parliament and working with the government than he's shown to date," he told Channel Seven's Sunrise.
"I really hope for the Greens' sake that it's not a return to the bad old days, where they just wanted to block everything."
But Senator Shoebridge said his attitude was caused by the government leaving Australians in the lurch, both economically and environmentally.
"Labor has left the progressive side of politics," Senator Shoebridge told ABC News Breakfast on Thursday.
"They have been marching to the right initially to meet whatever the coalition put to them. Now, they are marching even further to the right to meet what One Nation has put to them. Meanwhile, people are asking, well, hang on, what's the federal government is even for," he said.
The Greens have a big job to do if they have any hope of replacing Labor as a primary political party. They have held a relatively stagnant 13 per cent of primary votes in various polls since the 2022 election.
Asked if he planned to work constructively with the government in the upper house, Senator Shoebridge said it would require a change in the government's approach to interest rates, taxing large corporations and regulating artificial intelligence.
"We're in different political parties. We have very different political views of the world," he said of Prime Minister Anthony Albanese.
The influence of the UK Greens movement was impossible to miss, Monash University political science lecturer Nathan Fioritti said.
"This is lifted almost entirely from (UK Greens leader Zack) Polanski's rhetoric," Dr Fioritti told AAP.
"Whether a new leader can give new energy to that push and achieve cut through is probably the the challenge."
Since the federal election in May 2025, One Nation has surged in opinion polls, consistently eclipsing the coalition with first-preference votes in the high 20s.
In the same period, the UK Greens under Mr Polanski have lifted their share from nine per cent to a peak of 18 per cent at local government elections in May - well beyond that of their Australian counterpart.
Dr Fioritti said Australia and the UK faced similar political landscapes featuring a Labor party in office with a large majority and an increasingly disenfranchised voter base turning to minor parties particularly on the far-right.
"This is an opportunity for the Greens to refresh the leadership and prioritise presenting the party as a progressive or left wing alternative to One Nation for those disaffected voters," he said.
Before the leadership vote, former Greens MP Max Chandler-Mather had urged the party to follow the lead of its UK and New Zealand counterparts and introduce a vote for all party members to determine the leader.
Former deputy Mehreen Faruqi echoed the call in a post to social media in the hours after the leadership announcement.
