Federal Finance Minister Christian Lindner (FDP) has advised companies not to respond to Russian demands to pay for gas deliveries in rubles.
"We cannot accept blackmail," he said in an interview with Bloomberg TV on Monday.
The contracts were based in dollars and euros and "we recommend private companies to stick to these currencies".
Russian President Vladimir Putin announced last week that he would in future demand payment in rubles for natural gas deliveries to the West.
This would effectively force European companies to prop up the Russian currency after it slipped under sanctions in response to Moscow's war in Ukraine.
"Putin has to decide whether he accepts this or not - in any case we are ready and will find solutions," said Lindner.
"Our long-term goal is to be less dependent on Russian imports."
The G7 energy ministers unanimously rejected Putin's demand for ruble payments on Monday.
After the industrialized countries refused to pay for gas deliveries in rubles, Russia continues to threaten a supply freeze.
"No pay, no gas," Kremlin spokesman Dmitry Peskov told PBS.
Moscow wants to wait for the final answer from the EU and then determine the next steps.
"But we definitely don't intend to present ourselves as benefactors and deliver free gas to Western Europe," Peskov said.