However, in talks between the conservatives (CDU/CSU) and the SPD, who are working out the details of forming a coalition together, negotiators are discussing a possible 8-year extension, SPD sources told Reuters.

During the campaign before last month's general election, the CDU had promised to extend the life of Germany's 17 nuclear power plants as long as possible. The SPD had promised to adhere rigorously to the June 2000 law on phasing out atomic energy.

However, neither party wants the nuclear issue to be a stumbling block in the coalition talks, which are expected to last until next month, participants in the talks have said.

But not everyone in the SPD is happy about the possible compromise.

Michael Mueller, leader of the SPD's left wing in parliament, said in a statement there was no room for flexibility when it came to scrapping nuclear power in Germany.

"Whoever five years ago signed on to the deal to phase out nuclear energy and today demands that we get back into it raises the question of whether he's a reliable partner," he said. "Such a retrospective softening is non-negotiable for the SPD."