North Korea's issued a stark message to Australia at the weekend, accusing it of "blindly toeing the US line" and warning of a possible nuclear strike if it persists.
But Sydney Morning Herald security correspondent David Wroe told Morning Report that North Korea could not put a nuclear device on the end of a long range missile right now.
"They are making progress in their ballistic missile programme and their nuclear programme. They will be able to deliver a nuclear weapon on an intercontinental ballistic missile at some stage in the coming years. estimates vary, some people say it's as critical as 12 months, some people think it's more like five to 10 years."
Mr Wroe said the best option to avoid military conflict with the United States and its allies was for China to reign in North Korea.
New Zealand's Defence Minister Gerry Brownlee told Morning Report that it would mean the end of the North Korean regime if it attacked the United States in any way, and "self-preservation is a big motivation for that regime."
"There is a lot of sabre-rattling and attempts to destabilise with outrageous statements. But you have to take it seriously, because you never quite know."
The Prime Minister Bill English told Morning Report China and US were working together to avoid conflict
"The capacity of North Korea to deliver on those threats has yet to be tested, and we don't want it to be tested."