Controversial tax changes in the budget are a "step in the right direction" but the Greens want the government to go further before pledging to give their support.
The progressive minor party's vote is crucial to Labor's hopes of getting legislation through the Senate, given the coalition has vowed to repeal the changes to investor tax breaks if elected.
While the government has faced significant blowback from small business owners and landlords over the changes to the capital gains tax discount and negative gearing, Greens economics spokesman Nick McKim said Labor hadn't gone far enough.
"Faced with a once in a generation opportunity to shift more of the tax burden onto super wealthy people, and in particular super wealthy property speculators, Labor blinked," he told ABC Radio on Friday.
