The costed policy, to be released on Wednesday, would raise the tax-free threshold from $18,200 to $26,000, the first change to the threshold since 2012-13, and lift payments including the age pension, carers and JobSeeker by $1000.
The package is worth $22 billion a year, with Shoebridge arguing it would not add to the inflation pressures expected to prompt the Reserve Bank to lift official interest rates to their highest level since 2008 at its meeting next week. He will say the richest "1 per cent and their spinners" want people to ignore the key driver of inflation, "the surge in corporate profits flooding" the economy.
"Putting $1000 in people's pockets only adds to inflation if we don't also do something about corporate profiteering. So we'll take the heat out of the economy by trimming those corporate profits and sharing them with everyone," he will argue. "We'll tackle the cost of living by ending this raw deal on our resources and handing the money back to the people who need it. This is how government is meant to work."
An independent costing by the Parliamentary Budget Office found the policy would cost $65.1 billion over four years and $234.6 billion over the next decade, and would add $57.7 billion to the interest bill on government debt by the mid-2030s.
To pay for the package, the Greens propose a 25 per cent gas export tax, a proposal the federal government rejected before this year's budget, which would raise $17 billion a year, and an overhaul of resource rent taxes based on a proposal from the left-wing think tank Prosper, which could raise a further $28 billion a year.
The resources sector has pushed back against higher taxation, arguing it will kill new projects and hurt job opportunities in regional areas. The government instead adopted a gas reservation policy. Shoebridge said changes to coal royalties in Queensland since 2022 had not scared off businesses and had raised extra revenue for the state budget.
The Greens' plan is larger than the government's tax changes, which cut the bottom tax rate to 14 per cent and create the $250 "working age tax offset" from July 1, and is worth more in the short term than the Coalition's plan to index tax thresholds from 2028-29. Treasurer Jim Chalmers said this week the government was looking at further tax cuts, depending on the state of the budget.
The announcement seeks to shift the debate after weeks of questions over the party's governance and culture, following The Age's report that Shoebridge received a letter from seven active Greens members demanding an independent investigation into allegations that Senator Steele-John made inappropriate comments to women. Shoebridge has ordered an inquiry and Steele-John is on personal leave, missing this week's Senate estimates hearings.