Greenpeace said it was calling for "an immediate ban" on conventional light bulbs and demanding tougher European standards on energy efficiency.

"Light bulbs are an iconic example of the many energy-wasting products that are sold to consumers. (A light bulb) wastes 95 percent of its energy generating heat instead of light," it said in a statement.

The group, which crushed the bulbs with a bulldozer, urged consumers to switch to energy-saving bulbs, saying this move alone would "result in shutting down 25 polluting power stations in Europe."

Greenpeace said the protest marked the start of its international campaign to discourage the use of energy-guzzling devices.

It was timed to coincide with the opening of a two-day international conference on energy efficiency in the German capital on Friday.

The meeting is being hosted by Germany as current president of both the European Union and the G8 club of most industrialised nations.

German Environment Minister Sigmar Gabriel said in a statement it was vital for the industrialised world to work with developing nations to promote the efficient use of energy.

"We should cooperate with all big countries, in particular India and China, to help them to reconcile development and the protection of the environment and global climate."

German Chancellor Angela Merkel boasted recently that she has switched to energy-saving lightbulbs in her home.