People watch TV news showing the DPRK's breaking news, at Seoul station, in Seoul, the Republic of Korea, January 6, 2016. [Photo/IC]

China has always pushed for the denuclearization of the Korean Peninsula, maintaining that all relevant parties should refrain from unilateral moves detrimental to regional peace and stability.

President of the Republic of Korea (ROK) Park Geun-hye will convene an emergency security meeting on Wednesday.

The National Security Council (NSC) meeting will be presided over by President Park at 1:30 pm local time (0430 GMT), Park's spokesman said in a briefing.

Park is expected to discuss how to deal with the DPRK's fourth nuclear test, a surprise test of a hydrogen nuclear device.

Vice Foreign Minister of the ROK Lim Sung-nam said after an emergency meeting with diplomats that the fourth nuclear test was in violation of the resolutions of UN Security Council that bans the DPRK from conducting any nuclear test.

The vice minister said that the hydrogen bomb test is a serious challenge to world peace.

The ROK military reportedly strengthened its defense readiness after the nuclear test, saying that it was closely cooperating with the US forces over the raised tensions on the Korean peninsula.

The US government said Wednesday that it could not confirm that the Democratic People's Republic of Korea (DPRK) had conducted a hydrogen bomb test, while vowing to respond appropriately to any "provocations."

Japanese Prime Minister Shinzo Abe on Wednesday said the test was a "significant threat," according to Japan's public broadcaster NHK.

Japan has held its national security council meeting immediately after the quake was detected at around 10:30 am local time (0200 GMT) in the northeastern part of the DPRK.

"The hydrogen bomb test is a significant threat to Japan's national security and is unacceptable," the prime minister told reporters, adding Japan will consider sanctions against the DPRK as its nuclear test violates UN Security Council's relevant resolutions.

Japan lifted part of its own sanctions against the DPRK since the two countries reached an agreement that Pyongyang agreed to reinvestigate the whereabouts of Japanese nationals it allegedly abducted some four decades ago.

Abe also said Japan will work with the United States, the ROK, China and Russia to cope with the issue.

Meanwhile, Japanese Foreign Minister Fumio Kishida will hold talks with US Ambassador Caroline Kennedy over the nuclear test.