Berlin (AFP) - Germany's nuclear power plant operators are to pay more than 20 billion euros ($23 billion) into a special public fund to cover the cost of dismantling their atomic generators, a special government committee announced on Wednesday.

The committee was set up to ensure that the provisions set aside by the power giants would be sufficient and immediately available when needed.

Germany currently has eight nuclear power plants in operation, but plans to phase them all out completely by 2022 in the wake of the Fukushima disaster in Japan five years ago.

The cost of dismantling the plants and storing the waste from them is expected to cost tens of billions of euros and the operators -- E.ON, RWE, Vattenfall and EnBW -- have set aside 40 billion euros in their accounts for the purpose.

But the companies' current financial difficulties, caused by successive writedowns and restructuring, have given rise to concern that the money will not be readily available when the time comes.

To make sure it is, the commission has proposed that more than half of the sum -- around 23.3 billion euros for transporting and storing the nuclear waste -- be transferred as early as possible to a special fund run by the government.

For now, the operators have already set aside 17 billion euros in provisions to cover the waste from the plants.

But the committee is demanding an additional "risk premium" of 6.3 billion euros in exchange for which the fund would take the issue off their hands completely.

Nevertheless, the companies insist that they are not financially in a position to put up the additional funds.

Investors, on the other hand, appeared to view the matter differently and RWE shares were showing gains of nearly eight percent and E.ON shares more than four percent in the wake of the committee's decision.

At the same time, the committee ruled that the actual dismantlement of the power plants should remain the task of the operators, both financially and legally.

The committee's findings are likely to be adopted by the government and voted into law by parliament, either at the end of this year of the beginning of next year.