Shadow Chancellor Ed Balls has attempted to ramp pressure on George Osborne with a call for a two-year stamp duty holiday for first-time buyers.
Chancellor Osborne is under pressure from the right of his party to cut taxes.
Mr Balls said he could not yet promise to reverse any coalition spending cuts.
But he told the Sunday Telegraph that suspending the levy on properties worth less than £250,000 would help revive the housing market and the general economy.
Mr Balls is expected to explain how it could be afforded in his conference speech later today in Manchester.