Speeding up the restart of nuclear reactors halted in the wake of the Fukushima nuclear disaster may be Japan's "best option" for riding out any oil and gas shortages that result from sanctions imposed on Russia, a senior ruling party lawmaker said on Tuesday.

Japan has repeatedly said that, in the event of a possible U.S.-led embargo on Russian oil, it would work with Group of Seven nations to respond appropriately. There has so far been no impact on its energy supply from the situation.

Such an embargo would have a large impact on Russia, but it would hit Japan hard as well, said Itsunori Onodera, a former defense minister and senior lawmaker in the ruling Liberal Democratic Party.