Australian PM Malcolm Turnbull says Olympic unity won't demilitarise North Korea

Australian Prime Minister Malcolm Turnbull said Thursday he welcomed the recent dialogue between North and South Korea but marching together at the Winter Olympics won't denuclearise the Korean Peninsula.

Turnbull, visiting Japan to talk with Prime Minister Shinzo Abe about regional security, trade and other issues, cautioned against optimism.

"We have to be very clear-eyed about this," he told reporters.

"History tells us a very bitter lesson about North Korea. They have a long habit of ratcheting up their militarisation and then, you know, going into a lull for a while trying to persuade people that they're changing their ways, changing nothing and then ratcheting up again."

North and South Korea held rare talks in a border village this week where they agreed to form their first unified Olympic team, in women's ice hockey, and have their athletes parade together during the opening ceremony of next month's Winter Olympics in South Korea.

They'll present the plan to the International Olympic Committee this weekend in Switzerland.

Turnbull said pressure and sanctions against North Korea over its weapons programmes must be maintained.

In a news conference following their talks, Turnbull said he and Abe agreed on the importance of enforcing the sanctions "so this regime is brought to its senses and stop threatening in the manner that it does the peace and stability of our region."

Japan and Australia have been deepening their defence cooperation amid the tensions over North Korea's nuclear and missile development and China's expansion in the Pacific.