Analysis: Abbott may struggle to deliver budget surplus

A DECADE of federal budget deficits could be on the cards, with a new analysis finding the Abbott Government may struggle to deliver promised surpluses.

While the Coalition made no solid commitment to return to a surplus within a year, like former Treasurer Wayne Swan did, it did pledge to deliver a surplus "within a decade" before the election.

However, a budget analysis by Canberra economics firm Macroeconomics has reportedly found budget deficits stretching out until at least 2026-27.

The analysis has predicted a deficit of more than $6 billion in the first year the Coalition had hoped to deliver a $4 billion surplus - 2016-17.

It also shows unless major changes are made to the budget balance, deficits can be expected to grow to around $18 billion by 2020-21, and continue growing from then on.

The major problem remains that high-spending programs across several portfolios are out-stripping tax revenue - and the decline in the mining boom is only expected to worsen the situation.

The mid-year budget bulletin predicts the likely impacts of government decisions on the budget, and is usually released close to when the government releases its official figures.

While Prime Minister Tony Abbott has consistently said the government's official figures wouldn't be release until close to Christmas, he said on Monday it would likely be released "in the next week".

He did not go into detail regarding the expected release date of the Mid-Year Economic and Fiscal Outlook.

The news follows comments by Treasurer Joe Hockey a month ago that the budget update would be "substantially worse" than the last figures published at the September election.