Mr Šemeta believes there is currently the "right momentum" to push for such a tax, he told Brussels newspaper European Voice. The idea is to introduce a CO2 element into the 2003 directive on energy taxation to bring it in line with EU climate goals.

The new tax commissioner is finalising an impact assessment to assess draft proposals prepared last year by his predecessor. These aimed to provide a carbon price signal to sectors outside the EU's emissions trading scheme (ETS) such as transport.

The objective was also to improve links between the 2003 directive and the ETS scheme. There have been concerns of double regulation. The tax would be a minimum levy on the CO2 content of fuel for cars, heating or electricity production.

Finance ministers have given cautious backing to the plan. Nicolas Sarkozy is pushing for a similar tax in France but it is proving very difficult to implement. Ireland is also toying with the idea. Sweden, Denmark and Finland have had carbon taxes for years.

Despite the growing appetite for carbon taxation in Europe to complement emission reductions achieved through the ETS, Mr Šemeta's proposal faces a very serious hurdle: EU tax proposals require unanimity in the Council of Ministers.

And the fact is that not all member states are keen on the idea. Opposition from countries such as the UK, which objects on sovereignty grounds, has not changed. Britain has already opted for emissions trading to reduce CO2 in non-ETS sectors.

Commission president Jose Manuel Barroso's office was not available for comment when ENDS went to press but climate spokeswoman Maria Kokkonen said her commissioner was interested in "all methods" of reducing carbon emissions.