Catastrophes like Japan's 2011 tsunami cost the world more than $3.5 trillion over the last 30 years, a conference heard Wednesday, as the World Bank called for better disaster planning.

Policymakers meeting in Sendai, the main city in Japan's tsunami-ravaged northeast, were told that infrastructure and education in emerging economies should be designed to minimise the human and financial cost of natural disasters.

"We need a culture of prevention," said World Bank Group President Jim Yong Kim, as the Bank said insurers estimated the economic cost of disasters in the last three decades had topped $3.5 trillion.

"No country can fully insulate itself from disaster risk, but every country can reduce its vulnerability. Better planning can help reduce damage and loss of life from disasters, and prevention can be far less costly than disaster relief and response."

Kim was speaking after he and IMF managing director Christine Lagarde toured part of Japan's northeast coast that was pummeled by the huge tsunami in March last year.

They visited an elementary school where 320 people -- including 71 schoolchildren -- took refuge on the roof from monster waves that struck following a 9.0 magnitude earthquake.

The Arahama elementary school also served as an emergency evacuation centre when the waters had receded because of its stocks of blankets and other emergency goods, school principal Takao Kawamura said.

"Arahama was well-prepared for tsunami disasters and children had been drilled on evacuating to the school's roof," Kawamura said.

At a coastal children's park that has now become a dumping ground for tsunami debris, Lagarde told reporters she thought a lot about how youngsters had survived.

"It's a feeling of sorrow but at the same time when you listen to how (people here) go about reconstructing and dealing with all the damage, trying to be positive about it, it's very, very impressive," she said.

The tour took in parts of Japan's northeast where huge waves swept ashore, crushing whole communities and killing almost 19,000 people, despite well-drilled plans in a country prone to earthquakes and tsunamis.

Kim said the World Bank can learn from Japan's disaster management and reduce the price of calamities in other parts of the world.

"I think we have to remember this: This was probably the best country in the world in terms of preparation for disasters like this. And these kinds of disasters can happen to anybody," he said.

"The reason we are here is because we want to make the point that preparing for these kinds of disasters has got to spread."

Kristalina Georgieva, European Union Commissioner for international cooperation, humanitarian aid and crisis response, told AFP she was impressed by "the resilience of the Japanese people in their reconstruction efforts, and their generosity in sharing that experience with us".

Japanese Finance Minister Koriki Jojima said the so-called Sendai Dialogue should help make disaster planning an integral part of development in many emerging economies.

The Sendai talks are expected to feed into the communique to be issued on Saturday at the meeting of the Development Committee, a key decision-making body of the IMF and the World Bank.