The European Commission is considering for the first time allowing a group of EU states to harmonise their corporate tax bases, saying this would boost their competitiveness, documents obtained by Reuters show.

Common rules to calculate companies' tax base would please Germany and France, which have been calling for harmonised tax rates and a common base to fend off competition from new low-tax EU member states, and simplify life for big European firms.

But countries such as Britain and Ireland, both long-term opponents of any step towards common tax rules, are likely to reject such a proposal, even though the Commission does not suggest harmonising tax rates.

To bypass the opponents, the EU executive is ready to address a proposal only to a small group of states rather than to the full 25-nation bloc, an approach known as "enhanced cooperation" that has never been used before.

"The Commission will examine the possibility for an appropriate legislative initiative addressed to all member states or, if this cannot be attained within a reasonable period of time..., the possibility for an enhanced cooperation for the introduction of the common corporate tax base," the paper said.

EU finance ministers are due to discuss the document at a meeting in September in the Netherlands.

EU treaties normally require unanimity on tax proposals, allowing individual countries regardless of their size to block draft rules for years, as tiny Luxembourg did over a sensitive proposal to tax savings income held abroad.

The enhanced cooperation approach would allow a group as small as eight EU countries to go ahead with the tax plan.

The Commission has been working since 2001 on a plan to simplify the way companies calculate how much tax they owe. Business lobbies have repeatedly backed such a move to cut red tape, and improve transparency and legal certainty.

In February Internal Market and Taxation Commissioner Frits Bolkestein urged EU states to harmonise their corporate tax base and called for enhanced cooperation in this field.

The issue came to the forefront in recent months as France and Germany started to campaign for tax harmonisation for fear of losing revenue to new low-tax east European and Mediterranean EU members.

The Commission is opposed to setting minimum tax rates but favours simplifying the calculation of companies' tax base, also in view of the launch of new International Accounting Standards as from January 2005.