Any planned tax rebate as part of an economic stimulus package may not have a big impact on the US economy until Christmas, the director of the US’s Congressional Budget Office said on Tuesday.

Peter Orszag, whose agency provides impartial fiscal and economic advice to Congress, said that it would be a “major challenge” to send out tax rebates before June as the IRS is tied up with annual tax returns. “It is remarkable the world’s leading economic power cannot get cheques out faster than that,” he told a hearing of the Senate finance committee.