SIMON Crean has reportedly pledged to oppose any move by the federal government to tax earnings on superannuation accounts.
The Australian reports the Labor backbencher has called on his government to explicitly rule out changes that would retrospectively tax earnings generated by super accounts.
Mr Crean said doing so would be "tantamount to taxing people's retirement surpluses to fund our surplus".
He would not comment on whether he was prepared to cross the floor on the issue if necessary.
The government has been accused of engaging in class warfare over retirement savings, with the opposition warning Labor is planning a "sneak attack" on super funds in the May budget.
Trade Minister Craig Emerson on Sunday said his party had no plans to lift taxes on the superannuation of ordinary Australians but that super savings of the "fabulously wealthy" should be debated.
"People who are fabulously wealthy gaining effectively an advantage by putting their money into superannuation and being taxed at 15 per cent, where the everyday Australian may be facing a tax of 30 per cent, I think does enliven a debate," he told Sky News on Sunday.
"We are not seeking to impose new taxes on the superannuation accounts of ordinary Australians.
"But there is a legitimate debate about the very top end."