Speaking ahead of opposition leader Bill Shorten's Budget reply speech, Mr Bowen said, "we all know the taxation treatment of superannuation in Australia is just not sustainable".
"Joe Hockey’s own Budget, a couple of days ago, told us that. We see the concessional treatment of superannuation tax earnings, the cost to the Budget, doubling over just four years," he said.
Based on current trends, the cost of existing superannuation concessions will outstrip the cost of the age pension in a decade, he added.
"[Labor is] prepared to be honest with the Australian people and say that is just not sustainable – Australia can’t afford it," Mr Bowen said.
Prime Minister Tony Abbott, however, "doesn't have the guts" to address the issue going into a federal election, he said.
"The government’s own Commission of Audit pointed out that these tax concessions need to be dealt with. The government’s Murray Inquiry pointed out that 38 per cent of the tax concessions go to the top 10 percent of income earners," Mr Bowen said.
"The government’s own Taxation White Paper raised this issue and the government’s own Treasury Secretary has said that this issue must be dealt with."
Labor announced in April 2015 that, if elected, it would tax the investment earnings of retirees with account balances over $1.5 million.
