Chancellor Angela Merkel issued a government security decree Tuesday to suspend electricity production at all nuclear plants built before 1980, Britain's Financial Times reported.
Merkel called the nuclear disaster in Japan "a turning point in the history of technology-based society" but denied the re-examination of her nuclear policy had anything to do with a crucial regional election scheduled for the end of March.
Five federal states in Germany are home to nuclear power plants.
Last year, Merkel extended the proposed life of existing nuclear power plants in Germany from 2022 to 2036.
As polls revealed a swing in popular feeling against that decision, Merkel on Monday announced the three-month moratorium on the plan in order to consult nuclear-safety experts.
Environment Minister Norbert Rottgen said it was undecided how many of the units would be allowed to resume normal operations after the moratorium, and some officials said they expect at least two of the plants to be shut down for good.