Much has been done to prepare Vanuatu for big storms but it wasn't ready for the fury of Cyclone Pam. The category five system, with wind gusts of more than 300km/h, tore its way through the archipelago on Saturday causing extraordinary damage. About 70 per cent of the population may have been displaced and Vanuatu's President, Baldwin Lonsdale, says his nation's infrastructure is "completely destroyed".

Weather-related calamities like the one caused by Cyclone Pam are on the rise. The World Bank's Group vice-president and special envoy for climate change, Rachel Kyte, says the average annual number of disasters has almost doubled since the 1980s. The cost of those disasters has climbed from $US50 billion a year in the 1980s to just under $US200 billion a year in the last decade. Almost 75 per cent of those losses can be put down to extreme weather events.

In an ironic coincidence, a major conference on disaster risk reduction was held in the Japanese city of Sendai just as Cyclone Pam blew into Vanuatu. United Nations Secretary-General Ban Ki-moon told the meeting that climate change was making extreme weather events the "new normal".

That new normal poses a major challenge for Australia because our immediate region is especially prone to extreme weather. The likelihood of more frequent disasters in the Pacific will test Australia, the region's biggest donor and dominant economic power.

The latest World Risk Index, collated by the United Nations University, tells the story. Five of the 10 countries most exposed to natural disasters are near Australia and 12 out of the index's global top 20 are in the Asia-Pacific region.

Speaking from the Sendai conference, Richard Rumsey, a disaster response expert from the aid agency World Vision, said Cyclone Pam was a "wake-up call" on increased disaster risks for Pacific states.

"Small island communities are especially vulnerable to a worsening disaster scenario," he said. "Cyclone Pam is proof that the very future of island states is at stake."

The Abbott government was quick to send relief supplies, medical teams and disaster response experts to assist victims of Cyclone Pam. It also contributed $5 million to assist non-government relief agencies. Australia is also Vanuatu's largest bilateral aid donor, with an annual program worth $60 million.

It's the second time in 16 months that the Australian government and NGOs have mounted a big relief operation in the Pacific. In November 2013 the monstrous Cyclone Haiyan hit the Philippines, killing at least 6300 people and leaving more than half a million homeless. The newly elected Abbott government assumed a prominent role in emergency relief and reconstruction.

Robin Davies, a former top aid official who is now a professorial fellow at the Australian National University, says Australia will often be expected to take the lead in Pacific disaster responses.

"The reality is that Australia is viewed internationally as having a special responsibility for humanitarian and development assistance in the Pacific region," he said.

That will demand resources and preparation - the defence forces and other domestic agencies at both federal and state levels will need to gear up.

But this growing humanitarian challenge comes amid swingeing cuts to foreign aid by the Abbott government. Aid spending will drop from $5 billion this financial year to $4 billion in 2015-16, then to $3.7 billion the following year. By 2016-17 Australia's aid will be at its least generous level ever as a proportion of gross national income.

Such deep cuts threaten to diminish Australia's humanitarian capacity.

Extreme weather in the region will pose other tricky foreign policy challenges for Australia. Responding to disasters in the region will become increasingly costly and yet each humanitarian mission establishes a baseline against which the next one is judged.

"Once a government starts down this road, it cannot easily turn back," he said. "We cannot be seen to do more in response to a disaster in the Philippines than we do in response to a disaster in, say, Cambodia."