German opposition leader Friedrich Merz referred to Chancellor Olaf Scholz's decision not to allow the country's remaining nuclear power plants to continue running as "madness."
Addressing Scholz directly during a debate in the Bundestag parliament, Merz shouted: "Stop this madness!"
The head of the conservative Christian Democrats (CDU) added that the decision not to give the plants an extension could irrevocably damage Germany's status as a viable location to do business.
Scholz and German Economy Minister Robert Habeck of the Greens want to keep two of Germany's last three nuclear power plants on standby, instead of giving them a blanket lifetime extension as demanded by some in the opposition and in his ruling coalition.
Scholz responded to the comments by accusing Merz of sowing divisions.
"Those who talk about division endanger cohesion in this country, and that is the wrong thing to do now," Scholz told parliament.
"Do not underestimate our country – do not underestimate the citizens of this country," he said. "In difficult times, our country grows beyond itself. We have a good tradition of hunkering down when things get tough."
The German government is attempting to ensure energy supply for this winter against the backdrop of vastly reduced gas deliveries via the Nord Stream 1 pipeline from Russia.
Rather than being shut down as planned at the end of the year, the two power plants will be kept on reserve through mid-April in case they are needed to stabilize the electricity grid in southern Germany.
In an unexpected development on Wednesday, Habeck received a letter from the operator of the Isar 2 nuclear power plant saying that the plan to keep the plants on reserve was technically not possible.
Habeck expressed "astonishment" at the letter and accused Preussenelektra not having understood the concept of the emergency reserve.
"This has obviously passed the technicians at Preussenelektra by," Habeck said, adding that fresh talks would be held to clarify the situation.
The decision on nuclear power escalated a row within the ruling three-party coalition of Scholz's centre-left Social Democrats (SPD), Habeck's Green Party and the liberal Free Democrats (FDP).
The anti-nuclear Greens have been adamant about delivering on a decision, made when Angela Merkel was chancellor, to shut down the last three nuclear plants by the end of the year as part of Germany's drive toward increasing the share of renewable energy.
The pro-business FDP demand long-term, continued operation to help sink electricity prices.