North Korean leader Kim Jong-Un oversees "a very big machinery of people who have equally evil intent," Defence Minister Gerry Brownlee says.

Defence Minister Gerry Brownlee has accused North Korea of having "evil intent" and making "outrageous threats" – most recently against Australia.

Overnight on Saturday, North Korea's foreign ministry lashed out at Australia, warning that it was "coming within the range of the nuclear strike".

Speaking to TVNZ's Q+A on Sunday, Brownlee said he was not "particularly worried" about escalating tensions in the Korean peninsula but the situation was being constantly monitored.

ANDY JACKSON/FAIRFAX NZ Brownlee said when he had the opportunity he "never backed away" from discussing issues around the tensions in the South China Seas with Chinese military representatives.

"This is a country that is economically very depressed but is spending a huge sum of money sending some of those missiles into the Japan Sea and constantly threatening all those around with what they are trying to protect with some degree of military might," he said.

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"The difficulty is here you've got a leader [Kim Jong-Un] that people know very little about his regime but you would assume that underneath him there is a very big machinery of people who have equally evil intent.

"And so you've got to make sure that you think about the millions of North Koreans who are suffering under that regime at the present time," he told Q+A.

"It's North Korea that is sending the missiles into the Sea of Japan and making the various outrageous threats including the threats overnight to Australia."

Brownlee said while resolving the issues in the South China Sea were "for the countries most affected to determine", New Zealand continued to maintain there should be freedom of passage in the region.

"I've never backed away from discussing those things with Chinese military people when I've had the opportunity."

North Korea will undoubtedly be a talking point at a secretive meeting believed to be associated with the Five Eyes spy alliance – comprising the US, the UK, Canada, Australia and New Zealand – being held in Queenstown over the next few days.

Brownlee jokingly brushed aside an invitation on Q+A to confirm that Five Eyes spy agency bosses had arrived in New Zealand for the meeting.

"I thought it was the Bollywood actor who's down there [in Queenstown] this weekend. I thought that would be the reason for the excitement," he said.