But it acknowledged there is a concern over how the Stormont Executive is going to address unforeseen burdens on the public purse, in part related to the credit crunch.

Minister Nigel Dodds was due to address the financial situation in a statement to the Assembly today – his regular update on spending.

But it appeared last night that this may not occur amid the political deadlock in the Executive.

Instead, the Finance Minister is expected to make a statement to the media.

But speculation he may address a half-a-billion pounds shortfall in the 2008-09 government budget of £10 billion was flatly rejected.

A DFP statement said: "There is no 'black hole' in the Budget."

But it added: "The Finance Minister has already highlighted a number of significant issues that the Executive needs to consider in-year (2008-09), including equal pay in the Civil Service and the downturn in the property market. These are important issues that the Executive as a whole needs to discuss and consider."

Ulster Unionist finance spokesman David McNarry last night claimed a "serious shortfall" was emerging.

He said the Executive "cannot possibly now be living within its means" because of a series of cash blows which would make its financial provisions at the start of the year badly out-dated.

In part, the problems are linked to the credit crunch, rising fuel costs and nose-diving land and property prices – with deals such as the sell-off of Housing Executive stock and the £100 million Crossnacreevy land sale not now raising anticipated revenue.

But also there is the burden of having to fork out almost £200 million in Civil Service back-pay and another £200 million-plus in deferring water charges again.

"If you start piecing it together and adding it up, before you even know what the rise in fuel is costing government, or credit crunching, there is a black hole of half-a-billion (£500 million) at least," he said.

Stormont insiders noted that if the tap tax is not introduced, that falls into the next financial year (2009-10).

But Mr McNarry said that if there was not a black hole, the minister needed to spell out what the balance of the accounts was and any Executive contingency fund that exists.

He added: "Whatever way it is spun, it is serious that significant financial pressure is building and, at present, you would imagine may be set to grow.

"I know this is a sensitive subject, and I do not wish to scare people, but we need to know where we stand and if this is going to impact in frontline services."

The Department of Finance said Mr Dodds would address spending issues today.