EU competition regulators will simplify state aid rules allowing them to better target telecoms, energy and transport companies that enjoy unfair subsidies and tax advantages, the EU antitrust chief said on Thursday.

I want to shift the focus of our control on the cases that have a real impact on competition in the internal market and I want to investigate them thoroughly, EU Competition Commissioner Joaquin Almunia told a competition conference.

The examples that first come to mind are subsidised network industries, publicly supported incumbents in liberalised markets, and selective tax advantages, he said.

I believe that the Commission should have better tools to investigate these cases in depth and on its own initiative, he said.

Authorities in the 27-country European Union have to secure approval from the European Commission, which acts as competition regulator, before granting aid to companies. Recipients can be required to repay the funds if these are found to have breached EU rules.

The European Commission has taken EU governments to task in a number of cases for granting illegal subsidies to airlines, shipyards and banks, among other concerns.

Last week, Almunia ordered Germany and Belgium to retrieve millions of euros in illegal aid granted to their national postal agencies.

And the Commission is currently investigating energy deals between Russian gas export monopoly Gazprom and several of its main European customers.

Almunia said he would seek comments from other commissioners and EU governments before detailing the revised guidelines before the summer and implementation before the end of 2013.

(Reporting by Foo Yun Chee; Editing by Jon Loades-Carter and Rex Merrifield)