The Prime Minister and his Japanese counterpart Shinzo Abe reaffirmed their condemnation of North Korea's provocations during a phone call this afternoon.
The leaders agreed North Korea represents the most dangerous threat to regional peace and stability.
"If the leader of North Korea continues down this provocative track, the risk of war gets greater all the time," the Prime Minister later told Channel Nine's A Current Affair program.
"Kim Jong-un is behaving in a manner that is dangerous, illegal, reckless and provocative. He is threatening the region. He is threatening the world.
"If he starts a war, he will lose it instantly so it would in effect be a suicide note on his part."
The leaders agreed to maintain close cooperation as they try to make sure the pressure on North Korea to change course is at a maximum.
They also want to further encourage China to step up and use its economic ties with North Korea to help stop a further escalation of tensions.
"They have the ability to put the screws on North Korea economically. That will bring that regime to its senses," he said.
In Adelaide, Defence Industry Minister Christopher Pyne told reporters the government was considering upgrading the Navy's new air warfare destroyers to include missile defence shields in the wake of North Korea's "very irregular behaviour".
He said Australia may modify the $1.3 billion missile shield announced in June to be seaborne rather than land-borne, and indicated upgrades to the warfare destroyer capabilities had been already flagged.
"In the defence white paper, and the integrated investment plan, upgrades of the warfare destroyer capabilities have been already flagged," Mr Pyne said.
But he said a weapon similar to the United States' land-based missile defence shield could take as long as 10 years to build and cost at least $10 billion.
Protection from intercontinental ballistic missiles will also be considered for the nine frigates being built in Adelaide.
Foreign Minister Julie Bishop is hopeful the toughest sanctions slated against Pyongyang will soon bite and is confident Russia and China will get on board.
"If they are applied universally then North Korea will feel the brunt of these sanctions and realise that a penalty has to be paid for its illegal and provocative behaviour," she told Sky News.
