"There has to be a response. Such crimes must not remain unanswered," the defence ministry quoted Christine Lambrecht as saying in an interview with the public broadcaster ARD.
Berlin has so far resisted calls to impose an embargo on energy imports from Russia, saying its economy and that of other European countries are too dependent on them. Russia supplies 40% of Europe's gas needs.
Economy Minister Robert Habeck repeated the government stance on Sunday evening on the broadcaster ZDF, saying Germany was reducing its dependence on Russian energy but could not wean itself off entirely straight away.
Pressure is growing on and within the government to take more radical steps. Lambrecht said EU ministers would now have to discuss a ban, according to a Twitter post from her ministry.
The EU has been working on additional sanctions for some time but Economic Commissioner Paolo Gentiloni said on Saturday that any additional measures would not affect the energy sector.
German Chancellor Olaf Scholz said late on Sunday that Western allies would agree further sanctions on Russia in the coming days.