The Commons Treasury Committee is to study the Budget for evidence that details were leaked to the press before it was delivered to Parliament.
MPs on the cross-party select committee want to establish whether pre-Budget media coverage was educated guesswork or briefed by the Treasury.
Most of the key changes in Chancellor George Osborne's statement on Wednesday had been featured in the press in recent days and weeks.
Labour insiders suggested announcements had been made in advance because the two coalition parties each wanted to demonstrate what they had achieved in supposedly secret negotiations.
The Treasury Committee, which has criticised leaks and advance briefing in the past, is to hold a series of hearings next week to pick over today's Budget.
Among those to be grilled will be Mr Osborne and the independent Office for Budget Responsibility.
Tory MP Andrew Tyrie, the committee's chairman, said: "In its report on the Budget 2011, the Treasury Committee said 'we deprecate both leaks, and any advance briefing. Such activities are corrosive of good government'.
"The committee will examine this year's Budget in light of our earlier conclusions on pre-Budget press coverage."
Mr Tyrie said the committee would also be looking at whether the tax reforms announced in the Budget would be "fair, support growth and encourage competition, provide certainty and stability and be both practicable and coherent".