Foreign Minister Julie Bishop has hit back at North Korea after the reclusive state warned Australia could be the target of a nuclear weapons strike if it continued to "blindly" follow the United States.

Key points: N Korean accuses Australia of "spouting a string of rubbish" about isolated regime

N Korean accuses Australia of "spouting a string of rubbish" about isolated regime Spokesman said Julie Bishop could "never be pardoned" for saying North Korea's nukes were a threat to Australia

Spokesman said Julie Bishop could "never be pardoned" for saying North Korea's nukes were a threat to Australia Ms Bishop said the North Korea should help its "long-suffering citizens", not invest in arms

The threat from a spokesman for the North Korean Foreign Ministry came days after Ms Bishop used an ABC interview to warn North Korea's nuclear weapons program posed a "serious threat" to Australia.

The Pyongyang spokesman warned Ms Bishop to "think twice about the consequences to be entailed by her reckless tongue-lashing before flattering the US".

"What she uttered can never be pardoned," the spokesman said.

"The present Government of Australia is blindly and zealously toeing the US line," he said, accusing Australia of "spouting a string of rubbish".

"If Australia persists in following the US' moves to isolate and stifle North Korea … this will be a suicidal act of coming within the range of the nuclear strike of the strategic force of North Korea."

In response to the comments, Ms Bishop said Pyongyang's threat "underlines the need for the regime to abandon its illegal nuclear weapons and ballistic missile programs".

"These present a grave threat to its neighbours, and if left unchecked, to the broader region including Australia," she said.

"The North Korean Government should invest in the welfare of its long-suffering citizens, rather than weapons of mass destruction."

Sorry, this video has expired Pyongyang puts on show of force as Trump hardens North Korea rhetoric

Could North Korea actually strike Australia?

North Korea reportedly already has missiles which are theoretically capable of hitting Japan and the US military base in Guam, and there are concerns it is trying to develop an intercontinental ballistic missile which could hit targets as far away as northern Australia or the west coast of the USA.

But Professor John Blaxland, the acting head of the Strategic and Defence Studies Centre at the Australian National University (ANU), said the possibility of a strike hitting Australia remained a long way off.

"The prospect of Australia being struck by a ballistic missile from North Korea remains remote," he said.

"In addition, the prospect of them firing a nuclear weapon in a way that might affect South Korea or Japan, where Australians might reside, is still questionable."

He said experts were sceptical of whether North Korea had the ability not just to detonate a nuclear weapon, but also to project one.

"That's more complicated than just in a test underground ... its fairly sophisticated rocket science," he said.

"The question is whether or not they will in the next couple of years reach the stage where they can miniaturise their nuclear weapons capability and put it on top of one of their ballistic missiles.

"Pundits vary between two and four years, most say [that is] about four years away ... but it's an educated guess."

Last week, former special assistant to George W Bush, Dennis Wilder, told Lateline that North Korea could have that capability within four years.

But ANU professor Leszek Buszynski said it could take longer than that.

"I think a country like this that is working in isolation will find it extremely difficult to overcome these technical problems. I think it will take longer than that," he said.

Instead, he said the threats coming from North Korea were a sign the regime was "desperate".

"This is a regime that fears the United States may launch a pre-emptive strike," he said.

"I think in North Korea they take this very seriously indeed, because they've seen what the Trump administration has done in Syria ... and they would fear that the US would do the same to them."



Pence, after talks with PM, said US would 'deal' with North Korea

Ms Bishop's comments coincided with a visit to Australia by US Vice-President Mike Pence, who continued to condemn Pyongyang's weapons program at a time of heightened tension between the regions.

Mr Pence also thanked Australia for calling on China to exert greater economic and diplomatic pressure on North Korea.

"As President Trump made clear a few days ago, if China is unable to deal with North Korea, the United States and our allies will," he said, following a meeting with Prime Minister Malcolm Turnbull.

"Mr Prime Minister, know that President Trump and I are truly grateful to you for calling on China even this week to play an even more active and constructive role in addressing the North Korean threat."

Mr Pence would not rule out the use of military force in North Korea, repeating "all options are on the table", but stressed the US was focused on diplomacy at this stage.

Mr Turnbull meanwhile said it was "self-evident" China had the capacity to bring more pressure to bear on North Korea.

But he brushed off questions about whether Australia would join any military strike on the regime in the future.

"At this stage, the support we are providing is at the level of diplomacy [and] is of critical importance," Mr Turnbull said.

"We are quietly confident, I would say, that China will step up to this challenge and responsibility.

"China has a leverage, an ability to influence North Korea that far exceeds any others.

"As I said earlier this week, the eyes of the world are on Beijing. We seek leadership from China to join the leadership shown by the US and Japan and Australia and other nations around the world committed to peace."

Sorry, this video has expired Pence talks Australian alliance, pressure on North Korea (Photo Reuters: Jason Reed)

Labor echoes calls for China to act

Federal Labor MP Ed Husic said it was important the Opposition and the Federal Government maintained a bipartisan approach to North Korea.

Mr Husic said North Korean regime was one of the "biggest security threats to Australia" and the Asia-Pacific region.

He repeated Prime Mr Turnbull's call for China to place more pressure on the North Korean regime.

"I think it presents a serious concern," Mr Husic said.

"Their continual testing of missile technology has one end in mind and that is to get the furthest possible reach to where it can cause problems and increase tension."