Malcolm Turnbull will have to find other budget cuts after the election if coalition MPs succeed in heading off superannuation changes, says Labor.
The prime minister is facing calls from within his own ranks to tweak some of the changes to superannuation tax concessions outlined in the May budget.
Any post-election amendments to the policy - aimed at saving a net $2.9 billion over four years - would set back the government's plan to balance the books.
Labor leader Bill Shorten told reporters on the campaign trail in Sydney on Thursday superannuation should "not be a political football between various factions of the Liberal party".
"What other cuts will they have to implement to make up for the hole in their expenditure?" he said.
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Some Liberal MPs have been critical of limiting the tax-free status of retirement accounts over $1.6 million and transition-to-retirement arrangements.
Cabinet secretary Arthur Sinodinos has flagged the government will consult the party room on the legislation after the July 2 election.
But Treasurer Scott Morrison insists the superannuation policy outlined in the budget will be implemented.
Mr Morrison said Labor would set back economic growth, and the revenues that come with it, by proposing $100 billion in higher taxes over the next decade.
"We need to back the enterprises and those in our economy who are investing for jobs and growth in the future, not punish them with Bill Shorten's toxic taxes which are his chosen weapons in his war against business and his war on growth," Mr Morrison said.
Mr Shorten has promised to keep the coalition's deficit levy on top income earners in place over the next decade.
Asked whether this meant his government would deliver 10 years of deficits, he said Labor would maintain "rigid budget discipline" and reduce debt over the decade.
Mr Shorten continued his climate theme on Thursday with a pledge to ensure half of the power consumed by government departments and agencies would come from renewables by 2030.
Prime Minister Malcolm Turnbull is also in Sydney, maintaining focus on giving start-up businesses a leg-up.
