PRIME Minister Turnbull has urged about 200,000 Australians in China, Japan and South Korea to register on the Department of Foreign Affairs' Smart Traveller website amid mounting tensions on the Korean peninsula.
It would allow the government to immediately alert Australians of any changes to the situation and know where Australians were if an evacuation was necessary.
"The risk of war is greater than it's been since the end of the Korean war," Mr Turnbull told the Nine Network's Today Show this morning.
"The threatening conduct of Kim Jong-un is becoming more intense all the time.
"Having said that, I remain confident the global community will put more economic pressure on North Korea and that will bring the regime to its senses."
Mr Turnbull said if dictator Kim Jong-un carried out his threat and attacked the United States or one of its allies "there would be an overwhelming and massive military response" from America.
"It would be a suicide note on the part of Kim Jong-un but it would be a complete catastrophe," he said.
US WANTS OIL BAN ON N KOREA
The news comes as the US has called on the United Nations to slap an oil embargo on North Korea and freeze assets of leader Kim Jong-un.
A US-drafted resolution obtained by AFP also called for banning textile exports and ending payments made to North Korean labourers sent abroad, further depriving the regime of revenue to pursue its military programs.
The United States circulated the proposed resolution to the 14 other council members two days after US Ambassador Nikki Haley called for the "strongest possible measures" to be imposed on North Korea.
Ms Haley said on Monday that the United States was seeking a vote on the new sanctions on September 11.
The draft text takes aim directly at North Korea's leadership with a freeze on leader Kim's assets as well as those of the ruling Worker's Party of Korea and the government of North Korea.
Kim would be added to a UN sanctions blacklist that would subject him to a global travel ban, along with four other senior North Korean officials, according to the draft.
The state-owned Air Koryo airline would also be hit with an assets freeze, as would the Korean People's Army, the ruling party's central military commission and seven other government or party departments.
North Korea on Sunday triggered global alarm when it detonated what it described as a hydrogen bomb designed for a long-range missile, which was followed by signs that Pyongyang was preparing a new missile launch.
It came as US President Donald Trump said military action against North Korea was not the "first choice" of his administration on Wednesday, edging away from his harshest threats against the regime in Pyongyang.
After a phone call with Chinese counterpart Xi Jinping on how to deal with North Korea's threatening nuclear and ballistic missile programs, Mr Trump did not rule out military strikes, saying "we will see what happens." But, he indicated, other avenues for pressure would come first.
MATTIS: S KOREA DEENCE 'IRON-CLAD'
Earlier, the Pentagon said US Defence Secretary Jim Mattis had reassured his South Korean counterpart of the "iron-clad" US commitment to defend the American ally.
The White House also released details of the call on Tuesday with Prime Minister Malcolm Turnbull.
The White House said Donald Trump and Mr Turnbull "confirmed that their two countries will intensify joint efforts to denuclearise North Korea."
Mr Trump repeated his commitment to "defending the homeland, territories, and allies of the United States, using all available diplomatic and military capabilities."
The two leaders also discussed a range of global issues of mutual concern.
Mr Mattis and South Korean Defense Minister Song Young-moo spoke on Tuesday, and the US Defense Department said in a statement on Wednesday that Mr Mattis made clear that any threat to the US and its allies would be met "with a massive, effective and overwhelming military response."
Their conversation came days after North Korea's latest - and most powerful - nuclear test.
Mr Trump - in tweets after the North's test on Sunday - faulted South Korea for what he called its "talk of appeasement" toward the North, and didn't specifically mention that the US is obligated by treaty to defend its ally in the event of war.
Mr Trump is to speak on Wednesday with China's president.
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