Japan may not achieve its carbon emissions target if an ambitious plan to build more coal-fired power plants moves ahead, the environment minister said, underlining Tokyo's struggle to meet globally agreed goals to halt climate change.

Even as it champions the Paris climate agreement, Japan — the world's fifth-biggest carbon emitter — continues its massive reliance on coal and natural gas, putting it out of step with the rest of the Group of Seven bloc and even South Korea.

The industry ministry sees coal as an important part of the country's energy mix after the closure of nuclear reactors in the wake of the 2011 Fukushima meltdowns.