A feeling of relief swept among the ranks of the ruling Liberal Democratic Party amid intensifying criticsm from the opposition camp following Wednesday's Supreme Court ruling that judged a recent national election bordered on unconstitutionality but let the poll's outcome stand.

"I take the ruling seriously, and I hope to continue work on funadmental reforms" of the electoral system, said LDP member Masaaki Yamazaki, president of the Upper House, in a statement following the ruling.

The Supreme Court ruled the Upper House election in summer 2013 bordered on being unconstitutional due to an "outrageous" disparity in the weight of votes between districts, but it rejected the plaintiff's demand to invalidate the result.