The Government’s special savings incentive scheme will cost taxpayers €517m this year alone.
More than 1.1 million people lodged money in the scheme, which was designed to dampen inflation as people saved instead of spent.
The Labour Party accused Finance Minister Charlie McCreevy of concealing the real cost of the project, but the minister denied this.
He said he pointed out last year that it would cost €1bn per year if the maximum number of people participated.