German energy companies hit by Kremlin-imposed sanctions have been able to find alternatives to Russian gas, Economy Minister Robert Habeck said on Thursday, adding that the network regulator would provide details on the matter.

Russia has imposed sanctions mainly on European subsidiaries of state-owned Gazprom, including Gazprom Germania, an energy trading, storage and transmission business that Germany placed under trusteeship last month to secure supplies.

"Gazprom and its subsidaries are affected," Habeck told the Bundestag lower house. "This means some of the subsidiaries are getting no more gas from Russia. But the market is offering alternatives. They are getting gas on the market."

Russia's sanctions and an EU plan to ban Russian oil imports drove up energy prices on Wednesday, highlighting the economic costs of the bloc's push to untangle itself from the grip of Russian energy imports in response to the Ukraine invasion.

The decree signed by President Vladimir Putin forbids the export of products and raw materials to people and entities on the sanctions list, which includes the Polish part of the Yamal pipeline that carries Russian gas to Europe.

The European Union - which imports one-third of its gas from Russia - is split on the speed and scope of a phase-out of Russian energy imports. Hungary has opposed a ban on Russian oil.

"We are monitoring the situation. We have prepared ourselves for the situation. The regulator will inform you later today," said Habeck. "But the situation is such that the market is able to compensate for Russian gas. This conflict proves that energy is a weapon."

Russia's list includes Germany's biggest gas storage facility at Rehden in Lower Saxony, with 4 billion cubic meters of capacity and operated by Astora, as well as Wingas, a trader which supplies industry and local utilities.

Wingas has said it would continue operating under the new circumstances but would be exposed to shortages.

Rivals Uniper, VNG or RWE could be potential sources of supply to the market.

RWE CFO Michael Mueller said the sanctions had not affected his company's gas storage facilities.

"In view of a possible gas embargo, we have made provisions for our Russian supply contracts," he said. "At the start of the war, we had contracted a total of 15 terawatt hours until 2023. We have now reduced our exposure to less than 4 terawatt hours."