Neelie Kroes is unlikely to get member state approval

Competition Commissioner Neelie Kroes made the comments after she found she was unable to intervene in a proposed takeover between two Spanish firms.

Ms Kroes is unable to rule on Gas Natural's bid for Endesa as two thirds of their turnovers are inside Spain.

She wants this rule relaxed, but member states are likely to veto her calls.

Any change in the threshold would require the unanimous backing of EU nations, but analysts say a number of countries would oppose such a move as they are keen to see the creation of large "national champions".

Turnover rules

A European Commission spokeswoman told the BBC that Ms Kroes was particularly keen to see the two-thirds threshold relaxed for the energy sector, but also for other industries.

Gas Natural wishes to buy Spanish rival Endesa

The domestic turnover rule has been in place since the EU's merger regime was set up in 1989.

Under the rules, the Competition Commissioner can also get involved only if the companies concerned have a combined worldwide turnover of 5bn euros ($5.8bn; �3,4bn), and each has a turnover of 250m euros within the EU.

Gas Natural is seeking to buy Endesa for 22.5bn euros.