One of the nation's top military commanders says the global intelligence community is devoting enormous resources to understanding the rogue nation's capabilities after this week's successful long-range missile test.

Australia's northernmost cities are now potentially within the regime's range - but the ADF's Chief of Joint Operations, Vice-Admiral David Johnston, has sought to calm any immediate fears. 

"I think there is very little risk at the moment to the northern part of our country but we will continue to look at what is necessary," he said. "I don't think there's anything to suggest Australia has been or is a deliberate target."

He stressed a single missile test did not give a clear picture of North Korea's capabilities. "Given this development and also what's occurred in the peninsula over the last few months there is significant intelligence effort being attributed to it," he said.

The military will play a "supporting role" in responding to the latest crisis on the peninsula but for now the predominant response will be diplomatic. Defence planners will be watching closely the talks at the G20 in Germany in the coming days.

In one of the ADF's rare public briefings, Admiral Johnston also gave an insight into Australia's operations in the Middle East and the Philippines.

Australian forces have played a key supporting role in the battle for the Iraqi city of Mosul, which is now entering its final stages.

Mosul fell to Islamic State militants in 2014, the largest city to come under the extremist group's control. Iraq hopes to fully reclaim it in the coming weeks after months of intense, street-to-street combat, often in heavily populated areas in west Mosul. More than 1000 Iraqi soldiers have been killed and 6000 more wounded in the fighting.

ADF Super Hornet warplanes have bombed 456 targets around the city since Iraq and its coalition supporters launched an offensive against IS last year. Targets have included car bomb factories, weapons caches and tunnel entrances.

"The liberation of Mosul is now inevitable," Admiral Johnston said. 

Fewer than 400 fighters remain, controlling half a square kilometre of the Old City, he said, but they are increasingly willing to use civilians as human shields in a bid to restrict Iraqi ground forces and coalition air strikes.

The narrow streets of the older parts of Mosul are ideal for IS defenders, who have had time to build tunnels, defensive positions and interconnected strongholds. It's an ideal environment for snipers and concealed explosives, but hard for Iraq's heavy vehicles - and Australia's air support - who are trying to avoid civilian casualties.

However Admiral Johnston made it clear the liberation of Mosul would not spell the end of Australia's involvement in Iraq, as local forces look to recover and then take on other IS pockets throughout the country.

Admiral Johnston also confirmed two Australian Orion spy planes have started operating over the Philippines, providing imagery and other surveillance information to local forces battling a violent Islamist insurgency in Mindanao.

The planes are helping the South-east Asian nation track groups such as Maute, which has pledged allegiance to Islamic State and which stormed the city of Marawi in May.