The treasurer wants to start a conversation about the future of superannuation concessions that burden the federal budget, but hasn't changed his position on tax reform.
Jim Chalmers said the government can't ignore the cost of super tax concessions as the budget faces other pressures.
"We've got this big national advantage when it comes to super, we need to make sure it's sustainable and we need to make sure we can afford the various concessions into the future," he told ABC Radio National.
Dr Chalmers said since becoming treasure he hadn't tried to "pretend away" budget pressures, and tax elements of the superannuation system were one of them.
Tax breaks on super were introduced to encourage more people to save super rather than rely on the pension.
However, critics say the existing rules are being used by wealthy individuals to minimise their tax.
At the 2019 election, Labor proposed a policy to change super concessions and did not win office.
The treasurer said the government's priority, as flagged before the 2022 election, was multinational tax reform and said superannuation changes would not necessarily feature in the May budget.
"We haven't changed our view, we haven't taken any decisions," he said.
"But we should be up for a national conversation about the future of some of these concessions which cost the budget a lot of money."
Shadow Treasurer Angus Taylor said Labor had promised not to tinker with super at the last election.
"They weren't going to change super," Mr Taylor told ABC radio on Tuesday.
"It was made unambiguously by the prime minister before the election, and election promises like that really count."
The opposition has also been criticising Labor's proposed definition for superannuation that the government wants enshrined into law.
Mr Taylor said the definition, which includes a reference to preserving super for retirement, could stop people accessing super in times of need and that the government needed to clarify the nature of any planned restrictions.
