Google on Monday urged governments to get better at sharing information to allow citizens and first responders to make better use of the Internet during natural disasters.

At a conference in quake-prone Japan, Rachel Whetstone, the firm's senior vice president of public policy and communications, said some countries hesitate over disclosing data.

She said this prevents civil society from creating new services to help citizens in need.

"We certainly have found access to data has enormously improved many of our products, including maps," she said at Google's "Big Tent" conference, designed to discuss issues related to the Internet and society.

Roughly 430 participants gathered for the first "Big Tent" in Asia, held in this northern city, which was badly hit by the deadly earthquake and tsunami in March 2011.

"We are still seeing quite a few governments globally who are quite closed with their data. If we could have... greater access to that data, I think we could do even more amazing things," Whetstone said.

Tokyo was criticised for not publishing data it had as reactors at Fukushima went into meltdown, spreading radiation over a large area and forcing tens of thousands of people from their homes.

Public officials have said they were worried about sowing panic with information that was not readily understandable.

Engineers at the Google event also complained how Japan initially released radiation contamination data in PDF format, making it difficult for scientists around the world to easily edit and analyse them.

The global rush to access the data also caused the science ministry's servers to crash, prompting private IT firms and academics to scramble to help disseminate the data in easy-to-use formats with English translations.

"Scientists were very eager to attack this data if it could be organised," Brian McClendon, Google vice president of technology.

Google strengthened its disaster response operations after Hurricane Katrina hit the southern United States in 2005.

The IT giant offered "person finder" services in Japan to help reunite families along Japan's northern Pacific coasts which were hit by the 9.0-magnitude quake and subsequent deadly tsunami, triggering the Fukushima nuclear meltdown.

It also actively mapped areas hit by the tsunami, publishing photos of communities before and after the natural disaster.

But useful data from governments around the world in crises are difficult to collect, McClendon said.

"One of the challenges we have discovered in Katrina remains today, which is open data and being able to get it and deploy it and lay it on top of other data. It is what really makes a difference," he said.

Masaakira James Kondo, country manager for Twitter Japan, said he is now helping the Japanese government draft new guidelines for releasing information in crisis situations.

"There are not a lot of examples, where an earthquake of this scale hit a high-income nation that has Internet readily available," Kondo said.

"The government probably was the single entity that lost the public trust the most," he said.

The chaos in Japan after the triple disaster was amplified by fear of unknown health effects from the nuclear crisis, said Margareta Wahlstrom, UN special representative for disaster risk reduction.

Experts at the conference also stressed the importance of keeping a free flow of information on the Internet, even if it risked possible distribution of false information.

Meanwhile, consumers of information must also be educated to maximise the benefit of IT in disasters, said Wahlstrom of the United Nations.

"There is enormous work to do with the users -- communities, individuals, organisations, local governments -- about how to apply this data, and what to do with the knowledge actually at their fingertips today," she said.