Victorian MP Adam Bandt has vowed to increase pressure on the Morrison government to "act on climate change or go" after replacing Richard Di Natale as Greens leader.

Mr Bandt, the party's only lower house member, was elected unopposed by his colleagues at a meeting at Parliament House on Tuesday morning.

Queensland's Larissa Waters was elected co-deputy leader and Senate leader, also unopposed. Tasmania's Nick McKim, a former state Greens leader, was chosen as deputy Senate leader and co-deputy leader. His role was contested by senators Sarah Hanson-Young and Mehreen Faruqi, with two rounds of votes and a distributions of preferences needed before Senator McKim was declared the winner.

Mr Bandt used his first press conference as leader to say he would focus on community campaigning to build pressure on the government "to force them to act on climate change or go". His aim was for the Greens to secure the balance of power in both houses of parliament at the next federal election.