The draft targets the North's missile and nuclear programmes and invokes the UN's Chapter Seven, which could eventually involve the use of force. But divisions remain among key nations, with China unhappy with the new draft.
The underground test reportedly took place at 1036 (0136 GMT) on Monday in Gilju in north-east Hamgyong province. Russia is the only country to have confirmed that it was a nuclear explosion, amid speculation the test was not wholly successful.
North Korea has said it will take "strong countermeasures" against Japan if it goes ahead with new sanctions against the country, a senior North Korean diplomat was quoted as saying on Thursday.
"The specific contents will become clear if you keep watching. We never speak empty words," Song Il-Ho, the North's ambassador in charge of normalising relations with Tokyo, told Japan's Kyodo news agency.
North Korea's threats are part of a campaign to make the world think twice about its response to the nuclear test, says the BBC's Charles Scanlon in the South Korean capital, Seoul.
On Wednesday, Japan imposed its own tough new sanctions on North Korea, including banning all imports from the country. The sanctions are expected to be approved by the Japanese cabinet on Friday.
On Thursday, South Korea said it had not detected any abnormal radioactivity levels in its country after the alleged North Korea nuclear test.
North Korea warns Japan over sanctions
North Korea says strong countermeasures may be taken against Japan if it goes ahead with new sanctions against the country. The comments were attributed to a senior diplomat, Song Il-ho, on Thursday by Japan's Kyodo news agency.
"We will take strong countermeasures," he was quoted as saying in a statement from Pyongyang. "The specific contents will become clear if you keep watching. We never speak empty words."
Song is North Korea's ambassador in charge of diplomatic normalisation talks with Japan and was referring to Tokyo's decision to implement new steps in response to Pyongyang's announcement on Monday that it had conducted a nuclear test.
The additional sanctions proposed by Japan on Wednesday include banning North Korean imports and blocking ships from entering Japanese ports.
Historical factor
The steps will be approved by the cabinet on Friday, and Japanese officials said Tokyo would consider further measures depending on North Korea's future behaviour and developments in the international community.
Japanese Prime Minister Shinzo Abe said on Wednesday that Tokyo had decided on its own measures in view of the fact that a North Korean nuclear weapons programme, coupled with its missile arsenal, would pose a grave threat to Japan.
Song was quoted as saying that Pyongyang would regard Japan's measures as "more serious in nature" compared to others, because Tokyo has yet to adequately atone for its colonisation of the Korean peninsula from 1910 to 1945.
The US is seeking a United Nations Security Council resolution by Friday that would allow for punitive measures against North Korea.
Güncelleme Tarihi: 20 Eylül 2018, 18:16
