Thousands turned out in Germany Saturday for rival rallies for and against the closure of coal-fired power plants, as debate on the issue rages.

Some 15,000 people protested in front of the Chancellery in Berlin against government plans to gradually close down coal-powered plants.

Another 6,000 people from throughout Germany and elsewhere in Europe demonstrated against the use of coal, answering the calls of environmental groups such as Greenpeace and Bund to create a 7.5-kilometre (four-mile) long human chain around the huge Garzweiler open mine in the west of the country, organisers said.

"A large part of the population supports a gradual and socially acceptable withdrawal from coal, in order to achieve the (government) objective of reducing carbon dioxide emissions by 40 percent by 2020," from 1990 levels, the campaign groups said.

To reach this objective Germany's Economy and Energy Minister Sigmar Gabriel wants to end the reliance on coal which currently generates 40 percent of the country's electricity.

However his plans are opposed not only by the producers and the IG BCE energy union but also by members of Chancellor Angela Merkel's coalition government.

The government plans would mean the closure of the oldest coal-fired gas stations, around 10 percent of the total according to the authorities, 40 percent according to German power giant RWE.

As a main industrialised nation, environmental campaigners are looking to Germany to set an example for others to follow.

Magda Stoczkiewicz, director of Friends of the Earth Europe, said in a statement that "a successful German energy transition including a phase out of coal is of great international importance. Failure would make the rest of the world wonder: Why should we even try, if the Germans can't do it?"

Anne Stauffer, deputy director of the Health and Environment Alliance of over 70 medical and health organisations said that Merkel's "climate leadership... will echo in Europe."

At the Berlin demonstration, organised by the IG BCE, the union's president Michael Vassiliadis argued that the government policy amounted to a "social black-out throughout whole regions."

Gabriel, in an interview published by the Frankfurter Allgemeine daily Saturday, assured that Germany would still be using coal for "many years".

"However its importance will slowly diminish with the development of renewable energies," he said.

Germany has also committed to phasing out nuclear energy by 2022.