The Greens want to expand plans to boost the tax rate on high-earning superannuation accounts in order to secure support for the government's proposed changes.
The government has moved to double the tax rate on returns from superannuation accounts with more than $3 million to 30 per cent from mid-2025.
The minor party not only wants the threshold lowered from $3 million to $1.9 million, but also to have the full income tax rate on those accounts, instead of any concessional rate.
It also wants the policy to come in from July 1 this year.
Costings by the Parliamentary Budget Office show the Greens' policy would cover a total of 210,000 people and raise $54.6 billion over the next decade.
This compares to around 80,000 people covered by the government's model of a $3 million threshold and concessional tax rate, which would raise $2 billion in the first full year and $3.2 billion over five years.
"The Greens want Labor to eliminate all superannuation tax concessions above $1.9 million," Senator Nick McKim said.
"Our plan would only affect the top one per cent but it would start earlier, and tax twice as many people twice as hard as Labor's."
Prime Minister Anthony Albanese was dismissive of the push, saying on Saturday morning the government had got the balance right.
"The Greens will always find a reason to try to say that what Labour's proposing is something that they have a different position from," Mr Albanese told reporters in Melbourne's east during campaigning for a by-election in the marginal seat of Aston.
"But at least they're not like the 'no-alition' saying no to everything," he added in reference to the Coalition's promise to repeal the changes.
The Greens hold the balance of power in the Senate, with the government needing the support of the minor party and at least two independents to pass legislation.
Senator McKim said rather than using the superannuation changes to reduce debt, money would be better spent on raising income support or doubling the Commonwealth's rent assistance.
"We also urge Labor to direct revenue from curbing these concessions towards helping those who need it most," he said, referring to the government's plan to bank the savings.
The government is consulting on the changes before introducing legislation.
