Prime Minister Malcolm Turnbull says if North Korea launches an attack on the United States, Australia will join the conflict.

Key points: Mr Turnbull says the ANZUS treaty would be invoked if the US and North Korea go to war

Mr Turnbull says the ANZUS treaty would be invoked if the US and North Korea go to war PM spoke to US Vice-President overnight, discussing "the most dangerous flashpoint in the world today"

PM spoke to US Vice-President overnight, discussing "the most dangerous flashpoint in the world today" Tough new sanctions could force the regime to abandon its nuclear weapons program, PM says

The Trump administration has escalated its rhetoric against North Korea, after the rogue regime threatened to attack the US territory of Guam in the Pacific.

"America stands by its allies, including Australia of course, and we stand by the United States," Mr Turnbull told 3AW.

"So be very, very clear on that. If there's an attack on the US, the ANZUS Treaty would be invoked and Australia would come to the aid of the United States, as America would come to our aid if we were attacked."

Sorry, this video has expired Mr Trump made the comments before a security briefing at Trump National Golf Club in New Jersey. (Photo: AP/Evan Vucci)

Tensions have been rising on the Korean peninsula after North Korea carried out two intercontinental ballistic missile tests last month.

Mr Trump has warned he would not allow Pyongyang to develop nuclear weapons capable of hitting the US.

Mr Turnbull discussed North Korea's behaviour with US Vice-President Mike Pence overnight, calling it "the most dangerous flashpoint in the world today".

He would not say if Mr Pence sought any specific assurances of military aid from Australia.

But the Prime Minister said the terms of the Australia-US alliance were clear.

Kim Jong-un will soon receive plans from the army for a strike on Guam. ( Reuters: KCNA )

"But be under no misapprehension, in terms of defence, we are joined at the hip," he said.

"The American alliance is the absolute bedrock of our national security. If there is an attack on the US ... we would come to their aid.

"Now, how that manifests itself obviously will depend on the circumstances and the consultations with our allies."

The Prime Minister reiterated the same point later in the day after receiving a briefing on North Korea from military and intelligence officials in Canberra.

"Once again, we call on the North Korean regime to stop its illegal, reckless, provocative conduct which is putting the peace and the stability of the region at risk," he said.

Mr Turnbull said Australia and the US both still believed tough new sanctions on North Korea could force the regime to abandon its nuclear weapons program.

"[The Vice-President's] view and the view of the administration is that the way to resolve the situation with North Korea … is through these economic sanctions. That's the preferred way to deal with it," he said.

"But of course if North Korea decides to carry out some of its violent threats then obviously terrible consequences will follow, and there's no point ducking that inevitable consequence."

On Tuesday Mr Trump warned North Korea it would be "met with fire and fury like the world has never seen" if it continued to threaten the US.

The US President has not backed away from those remarks, today saying his language could have been even tougher.

"Maybe it wasn't tough enough. They've been doing this to our country for a long time, for many years," he said.

The US Pacific territory of Guam is located in the Pacific Ocean. ( ABC News )

'Target on our back'

The Prime Minister used stronger language on North Korea than the Foreign Minister.

Yesterday, Julie Bishop said there was no "automatic trigger" for Australia to join a war between the US and North Korea, because Australia was not a party to the armistice declared at the end of the Korean War in 1953.

She acknowledged the ANZUS treaty imposed separate obligations on both countries but also said it only required Australia and the US to "consult" with each other, if either country was threatened or attacked.

"As far as the ANZUS Alliance is concerned, that is an obligation to consult. But of course we have been in constant discussion with our friends in the United States," she said.

Meanwhile, the Greens have reacted angrily to the Prime Minister's comments — accusing him of inflaming tensions in the region.

"Malcolm Turnbull by backing Donald Trump has just put a target on our back," Greens leader Richard Di Natale said.

"What we've got is two dangerous, paranoid and unhinged world leaders goading each other into a conflict which puts the very survival of each and every person on the planet at risk.

"If there was ever a clearer example of why Australia needs to ditch the US alliance and develop an independent, non-aligned foreign policy, this is it."

Calls for missile defence shield

Anxiety over North Korea's nuclear tests has also stoked debate about whether Australia needs to develop its own missile defence shield.

Former prime ministers Kevin Rudd and Tony Abbott have separately called for the Government to consider developing a shield which could provide protection from intercontinental ballistic missiles.

South Korea has been installing American Terminal High Altitude Area Defence (THAAD) launchers, despite fierce opposition from China.

But Mr Turnbull said the Defence Department did not believe a THAAD missile defence system was suited to Australia.

"THAAD is designed to provide protection for relatively small areas against short-to-medium-range missiles, so it's deployed in Israel, it's deployed in South Korea," he said.

"It's not designed to provide protection against long-range intercontinental ballistic missiles of the sort North Korea has recently tested."