Treasurer Wayne Swan this week conceded that Labor would not be able to return the budget to surplus in 2012-13, despite its promise to do so for the past two years.
Trade Minister Craig Emerson has told Sky News the figures at the time of the promise had indicated a surplus was on track.
But he says the situation has changed.
"If you look to Julia Gillard's statement and Anthony Albanese statements, they are based on what where the best figures available to the government at that time. New figures came in, I think it was on Thursday, and on the basis of those new figures, with revenue not growing as strongly as expected because of the surpressing effects on profits of an unusually high exchange rate, that's what that decision/that announcement was made."
The federal opposition has promised to deliver a budget surplus if it wins next year's election.
The opposition's climate spokesman Greg Hunt has told Sky News the Coalition can bring the budget back to surplus by cutting on expenditure.
"The history is very clear. We delivered 10 out of 12 surpluses, we have economic management in our DNA, the Labor Party under successive governments has delievered 11 out 11 deficits -- those aren't random figures, that isn't random chance."
The federal government says attacks from the opposition that it has broken another promise are unfounded.