German Chancellor Olaf Scholz on Wednesday raised the possibility of keeping nuclear plants going as he accused Russia of blocking the delivery of a key turbine to throttle gas supplies to Europe.

The continent's biggest economy has been scrambling for energy sources to fill a gap left by a reduction in gas supplies from Moscow.

Standing next to the turbine, Scholz said that extending the lifetime of Germany's three remaining nuclear power plants "can make sense".

The power stations, which are set to be taken off the grid at the end of the year, were "relevant exclusively for electricity production, and only for a small part of it", Scholz said.

In total, the nuclear fleet accounts for six percent of Germany's electricity output.

The government has said it will await the outcome of a new "stress test" of the national electric grid before determining whether to stick with the long-planned phase-out.

Former chancellor Angela Merkel spectacularly decided to ditch atomic energy in 2011 following the Fukushima nuclear disaster in Japan.

Extending the lifetime of the plants has set off a heated debate in Germany, where nuclear power has been a source of controversy stretching back before Merkel's decision.

Germany has already moved to restart mothballed coal power plants to guard against an energy shortfall.

The squeeze comes as Russia dwindles supplies of gas, which Germany has long relied on to power industry and heat homes.

Russian energy giant Gazprom has chalked up limited supplies to technical issues.

The delayed return of a turbine from Canada, where the unit was being serviced, was behind the initial reduction in deliveries via the Nord Stream 1 gas pipeline in June, according to Gazprom.

Supplies via the energy link were further reduced to around 20 percent of capacity in late July, after Gazprom halted the operation of one of the last two operating turbines due to the "technical condition of the engine". (AFP)