The president of the European Commission has said he wants new laws to dismantle energy monopolies in the 25-nation trading bloc.
Jose Manuel Barroso said new legislation, perhaps paving the way for a pan-European industry regulator, were timely to allow smaller competitors to enter the market.
In a bid to spur on competition in the sector, and to allow the trading bloc to manage rising oil prices and increased dependence on imports, he warned large "vertically integrated" groups could be forced to unbundle power transmission networks and gas pipelines to new owners.
"In energy terms I can tell you that I am more convinced than ever that we need new legislation concerning regulation," he told the Financial Times.
His comments came as EU energy firms such as EDF and Suez-GDF of France and Enel of Italy seek to merge.
The Spanish government is expected to allow E.ON to take over the country's largest energy group, Endesa, within the next few days.
Elsewhere, the Belgian government is opposed to the merger between Suez and GDF, claiming it would negate competition in the country.
The commission is aiming to create a single EU energy market.