The Federal Government’s budget surplus has been revised down to $5 billion amid a forecast revenue slump.

The slump in forecasted revenue has wiped away almost half the surpluses originally tipped for the next four years.

The mid-year budget unveiled this week includes predictions for a surplus of $5 billion this financial year, down from the $7.1 billion estimated ahead of the federal election.

The Government still expects to be in surplus each year for the next four years, though it will be closer to $23.5 billion than the $45 billion trumpeted in the budget.

The Mid-Year Economic and Fiscal Outlook (MYEFO) also shows the Government expects revenue will be $3 billion lower than earlier projections, while treasury officials have slashed forecasted revenue by more than $32 billion.

The Government has blamed the budget hit on “weak momentum in the global economy” and “the devastating effects of drought and bushfires”.