The Finance Bill, which gives effect to the Budget, will be published by the Government tomorrow.

A spokesman for the Minister for Finance, Mr McCreevy, would not say yesterday whether the Government planned any major amendments to the Budget, which was introduced in December. It was most notable for its decision to implement plans to decentralise 10,000 civil servants and various Government departments out of Dublin.

The Budget's main financial measures did not not include any increase in tax bands and more than one-third of taxpayers will pay the top rate of 42 per cent when changes become law.

Fine Gael sought to concentrate the debate in advance of the Bill on its demand for long-term planning and more fairness in the application of the tax code.

The party's finance spokesman, Mr Richard Bruton, said Mr McCreevy should "proof" his budgets against long-term strategic objectives and subject his spending and tax plans to scrutiny before making any commitments.

"Tax decisions are almost invariably ad hoc, based on hunch rather than analysis," he said.

"Huge swathes of income are given relief without proper knowledge of the implications. There is no cap on the degree to which well-placed individuals can reduce their tax contribution to zero."

Mr Bruton added: "How this squares with the public interest is never considered."

Labour spokeswoman Ms Joan Burton said the Bill was likely to contain extensions on a set of property-based tax shelters that were already "creating unacceptable levels of inequity and unfairness in the income tax code".

"On the one hand, the Bill will allow very wealthy people the opportunity to reduce their tax exposure through these shelters," she said. "At the same time, it will deny modest income-earners a fair indexation of the income threshold at which they start to pay the higher tax rate. On this anomaly alone the Bill deserves to fail."