BERLIN - The German government is mulling scrapping a disputed nuclear fuel rod tax to relieve financial pressure on power firms so that they can invest in alternative clean energy sources, a newspaper reported on Wednesday.

The Financial Times Deutschland newspaper cited sources in Chancellor Angela Merkel's centre-right coalition as saying that in return for having the tax eliminated, firms would agree to drop opposition to an earlier exit from nuclear energy.

In March, Merkel dramatically reversed a decision from last year to extend the lifespan of German nuclear power plants, in response to the Japanese nuclear power crisis. She now backs proposals to shut all 17 German plants down within a decade.

The tax agreed last year would have imposed a charge on utilities per megawatt hour from 2017 in exchange for what was then expected to be an extension of the plants' lifespan.

"Everything points to (the tax) being eliminated," one of the coalition sources was quoted as saying. Government sources were not immediately available to comment on the report.

Merkel has imposed a three-month moratorium on operation of the oldest seven nuclear plants.

Her government has signalled that the seven plants taken offline will remain so and her cabinet is due to decide on a nuclear exit strategy on June 6.

One party in her coalition has adopted the official goal of exiting from nuclear energy by 2022, while a series of regional election setbacks for Merkel - and gains for the Greens - have been blamed on her confused nuclear stance.

Germany's nuclear plants are run by RWE , E.ON , Vattenfall and EnBW .