Labor has offered to work with the government on finding budget savings in superannuation, but doesn't want it rushed and will demand any changes are fair.
Opposition superannuation spokesman Jim Chalmers says the proposed $500,000 cap on non-concessional contributions backdated to 2007 is causing voters most concern.
Dr Chalmers says Labor won't rule out supporting the changes.
"If there's a case that can be made that they're workable and fair, then we will support them," he told ABC radio on Tuesday.
"If there are improvements which could be made, for example, if you could make that $500,000 cap prospective rather than retrospective, that's worth a discussion, that's worth looking at."
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Opposition Leader Bill Shorten has called for an independent expert review to examine whether or not the changes are retrospective.
The controversial changes have been blamed for some of the voter backlash suffered by the coalition at the election.
The Australian reports senior Liberals including deputy leader Julie Bishop and ministers Christopher Pyne and Peter Dutton warned the prime minister and treasurer about the potential backlash.
The coalition party room is expected to discuss the issue when it meets next week.
John Daley, chief executive of the Grattan Institute think tank, says the changes are not retrospective.
"Nobody's position is made worse because of something they did in the past," Mr Daley told ABC radio.
"It's just that as a result of these changes, their position going forward won't be quite so good as it might have been otherwise."
Government minister Scott Ryan said while he couldn't say no one had approached him since the budget with concerns about superannuation, he didn't think it was a key factor in the election.
"When you look at where people were going to be negatively impacted by these superannuation changes, there wasn't a large voter response," he told Sky News.
He indicated the government still intends to take its plans for superannuation to a vote in parliament.
The SMSF Owners' Alliance, which represents self-managed retirees, said in a statement Labor should refuse to back the law changes until there is "genuine consultation".
"Superannuation is too important to the lives of most Australians to be subject to piecemeal change according to the government of the day," the alliance said.
The debate comes as Mr Shorten weighs up a reshuffle of his front bench in the wake of the federal election loss.
Andrew Leigh, Sam Dastyari and new MPs Linda Burney, Matt Keogh, Anne Aly and Tim Hammond are being flagged for promotion.
