Foreign Minister Hirofumi Nakasone also called North Korea’s missile and nuclear programs a serious threat to regional and global stability.

"China continues to modernize its nuclear arsenals but has not undertaken any nuclear arms reductions," Nakasone said. "Nor does the country disclose any information on its nuclear arsenals."

Nakasone, speaking at a Tokyo hotel to outline Japan’s initiative for global nuclear disarmament, also urged other nuclear states, including the U.S., Russia, India and Pakistan, to step up their effort toward nuclear disarmament.

"Improved transparency and nuclear weapons reduction by China and other nuclear states are vital for the progress of global nuclear arms reduction," he said.

Beijing says its nuclear weapons development is for defense only.

China’s annual double-digit percentage increases in military spending have rattled its Asian neighbors, and Washington has warned Beijing’s failure to clearly declare its intentions could prompt further unease. Japan also has repeatedly criticized Chinagrowing military spending and its murkiness.

Nakasone’s speech came before Prime Minister Taro Aso heads to Beijing on Wednesday for a two-day official visit.

Nakasone praised President Barack Obama’s recent speech mapping out his vision to achieve a world without atomic weapons. Nakasone said Japan fully supports Washington’s initiative.