Prime Minister Malcolm Turnbull says recent calls for terrorist attacks at Australian landmarks should be taken seriously.

Key points: Malcolm Turnbull says threat of 'lone actor' terrorists has to be taken seriously

Malcolm Turnbull says threat of 'lone actor' terrorists has to be taken seriously PM is in Laos, where security is high as leaders gather for ASEAN summit

PM is in Laos, where security is high as leaders gather for ASEAN summit South China Sea, North Korea will also be focus of talks

An Islamic State propaganda magazine has called for 'lone wolf' attacks at locations in Sydney and Melbourne.

The threats have been played down by Victorian Premier Daniel Andrews and by the state's police commissioner but not by the Prime Minister, who said recent attacks around the world showed the danger of so-called lone wolf terrorists.

Speaking in Laos, Mr Turnbull said the calls for violence in Australia represented desperation on the part of the Islamic extremists.

"As Daesh (Islamic State) comes under more and more pressure on the battlefield in Syria and in Iraq — as it is rolled back, as its territory is being taken back — it will resort to terrorist activities outside of the Middle East," he said.

"The capacity of Daesh, of course, is much less than they proclaim it to be.

"But we do have to be very alert to the actions of these lone actors — individuals who, as I've described in the national security statement last week, for a variety of reasons, may be radicalised.

"(They are) often associated with mental illness, frankly, can be radicalised very quickly and engage in very destructive, lethal conduct, as we saw in Nice, for example."

Extra security as Asian leaders converge on city

Mr Turnbull, who is in Laos for regional talks about security and economic ties, said regional cooperation was needed to keep Australians safe from extremist violence.

Laos's capital Vientiane, has an extra layer of security for the big name guests attending the South-East Asian and East Asian summits.

Malcolm Turnbull enjoys a special Prime Minister's blend at a Vientiane cafe. ( ABC News: Liam Cochrane )

US President Barack Obama, Russian President Vladimir Putin and Chinese Premier Li Keqiang are in the city for the talks, which start today.

"This is the premier forum for discussing and resolving issues of national security, economic security in our region. So I'm very pleased to be here," Mr Turnbull said.

Mr Turnbull said the recent missile tests by North Korea would be a key issue.

"These represent continued destabilising, dangerous and provocative conduct," he said.

Mr Turnbull's visit has also included a coffee stop at a local cafe, owned by a Laotian who worked as a barista in Sydney.

The cafe even created a special 'Prime Minister's Blend' for the occasion.

South China Sea conflict a key issue of ASEAN summit

The ASEAN summit is also likely to focus on the conflict over the South China Sea.

Five ASEAN member states have overlapping claims with China and tensions have been rising in an important sea channel that sees $5 trillion worth of trade pass through each year.

A recent court ruling at the Hague found that China has no legal basis for its claim over the Scarborough shoal.

But Beijing's allies — Cambodia, Laos and Brunei — have ensured that a draft communique does not contain any reference to that ruling, and Philippines President Rodrigo Duterte said he would not be raising the decision at ASEAN.

But then Mr Duterte is known for his crass, off-the-cuff comments, including calling Mr Obama a "son of a whore" recently — adding an element of volatility to these often staid summits.