* Greenpeace calls for state to run nuclear dismantling fund
* Environment minister says Greenpeace proposal can be examined
* Major utilities reject idea
DUESSELDORF, Germany, April 11 (Reuters) - Germany would consider ringfencing billions of euros to be put aside by utilities for disposing of radioactive waste, the environment minister said, to ensure decommissioning of the country's nuclear power plants is completed decades from now.
He was speaking on Wednesday in response to a call from environmental group Greenpeace that wants the government to administer some of the money earmarked for nuclear decommissioning.
German Chancellor Angela Merkel's decision last year, following Japan's nuclear plant disaster, to phase out nuclear power by 2022 has thrown big utilities on the defensive, weakening their finances and forcing them to rethink their business models.
Germany's top four nuclear operators - E.ON, RWE , EnBW and Swedish's Vattenfall - are footing the bill to dismantle the plants and dispose of radioactive waste. They have already made provisions of more than 30 billion euros ($39.3 billion).
Managing the disposal of waste will take decades after the last nuclear plant is due to shut in 2022 and Greenpeace fears that the companies may not be able to honour their obligations in the future or could try to wriggle out of them.
Parking the companies' money in a separate state-run fund would protect German taxpayers should one or more of the firms become insolvent, Greenpeace said.
"This is an idea that can be examined," Environment Minister Norbert Roettgen told Reuters on Wednesday, adding it was clear that the operators of nuclear plants were responsible for dismantling them.
"We need to look at whether a combined fund is a better solution than relying on individual responsibility," he added.
Greenpeace has also called for provisions to be raised to 44 billion euros.
Germany's utilities rejected the Greenpeace proposal for a public-administered fund, arguing that the existing system of provisions had proved sufficient.
"The German provision system has proven successful for decades and there is no factual reason to change it. There has been no case when provisions were not available for dismantling," E.ON, Germany's largest utility, said. ($1 = 6.7977 Swedish crowns) ($1 = 0.7644 euros) (Reporting by Tom Kaeckenhoff in Duesseldorf, Hendrik Sackmann in Stuttgart, Vera Eckert in Frankfurt and Gernot Heller and Noah Barkin in Berlin; Writing by Christoph Steitz; Editing by Erica Billingham)