The Albanese government is pushing departments to defer spending beyond the next financial year, bureaucrats claim, which would minimise the size of the budget deficits to be revealed during the election campaign.

With an election due by May 17 at the latest, the Albanese government can no longer claim the budget is in surplus. The mid-year budget update to be released on Wednesday will confirm it is back in deficit and will stay that way for the foreseeable future.