Chancellor George Osborne is set to enshrine in law the coalition's plans to eliminate Britain's underlying budget deficit by 2017/18.
The move - expected to be unveiled around next week's Autumn Statement - was being seen at Westminster as an attempt to set a trap for Labour.
By staging a pre-election Commons vote on the deadline to balance the nation's books, Mr Osborne would hope to put Ed Miliband's party on the spot by forcing them to either accept Tory and Liberal Democrat plans or appear soft on the deficit.
While the two coalition parties are agreed that the cyclically-adjusted current deficit should be eliminated by 2017/18, shadow chancellor Ed Balls has so far said only that he will aim to run a surplus on the current budget "as soon as possible" and by 2020 at the latest.
A report in the Financial Times suggested that Mr Osborne may seek to enshrine the 2017/18 target in law by proposing a change to the Government's fiscal mandate, which currently requires him to bring the current deficit into balance on a five-year rolling timetable.
But aides of the Chancellor described reports of his plans as "speculation".