The German and British leaders will officially open the world's biggest high-tech fair on Sunday, amid global debate about data security following revelations of mass US and British online snooping.

Chancellor Angela Merkel joins fellow conservative Prime Minister David Cameron to inaugurate the CeBIT in the northern German city of Hanover, 10 days after her high-profile London visit.

Berlin and London have both been caught up in the surveillance scandal revealed by rogue US intelligence analyst Edward Snowden, but Russia's brinkmanship over Ukraine may well be the main focus of their bilateral talks.

Britain is the partner country at this year's CeBIT, which opens its doors for a five-day run on Monday and is focused on the theme of "datability", the ability to use vast amounts of data quickly and responsibly.

About 3,400 international exhibitors will set up shop in the hangar-like halls of the sprawling IT fair, where futuristic robots and the fresh blood of 300 start-ups will mix with cutting-edge computer technology.

"What we've learned through the disclosures by Mr Snowden is that this topic of 'datability' is of course closely tied up with the issue of security," said Hartwig von Sass, spokesman for organisers Deutsche Messe.

"We want this issue of data security at the CeBIT because we think that 'big data' usage or 'datability' cannot be discussed without the security aspect," he told reporters ahead of the event.

Around 500 companies will exhibit digital security solutions, he said, noting an IT industry trend towards protecting data through the use of objects such as armbands or rings, rather than passwords.

After all, he stressed, many German online users still don't know about securing their data with hard-to-crack and complex passwords, with the most popular choices still being "password" and "123456".

- Political, social dimension -

At last year's CeBIT opening, Merkel showed off her ultra-secure new smartphone, only to learn months later that US intelligence had allegedly eavesdropped on her mobile phone conversations, as well as hoovering vast amounts of online data and telephone records from average citizens.

Merkel has since raised the need to bolster citizens' data protection by building up European communication networks that bypass US Internet giants.

Sass pointed to the exponential growth of global data, saying that the equivalent of all data ever required by humans through to the year 2003 is now produced in 10 minutes worldwide.

Against this backdrop, CeBIT organisers would also explore the potential benefits of so-called "big data" in fields such as medicine, traffic management and business.

Britain-based analyst Thomas Reuner, of Ovum's IT Services, said the sector's grappling with serious issues such as data security showed it had matured into handling its responsibilities.

"To talk about complex IT issues is not sexy, it's not marketing," he said. "But it's a reflection of an industry growing up."

High-tech gadgets will also be much on display at CeBIT, including "Charlie", the first robot with an actuated spine and feet that can "feel", developed by the German Center for Artificial Intelligence with Bremen University.

And after the excited chatter about the 3-D printer, the fair will present the new kid on the block -- a pen that can draw 3-D objects in the air.

Microsoft, Samsung Electronics and IBM are among the big hitters expected at the CeBIT, where China, with 500 companies, will have the biggest presence among the 70 countries taking part.

Britain has tripled its presence for its year in the limelight.

A British Embassy spokesman in Berlin said the move was "very much a demonstration of the strength of the UK economy at the moment and the IT sector is an important part of developing a modern, flexible, competitive economy".

The IT sector is worth �58 billion (70 billion euros, $97 billion) for the British economy and employs 1.3 million people in Britain, he said.

Even if CeBIT has raised exhibitor numbers by five percent from 2013, the fair is a far cry from its glory days at the height of the dot-com boom.

It also comes on the heels of the Consumer Electronics Show in Las Vegas and Mobile World Congress in Barcelona, but Sass said CeBIT's forte was its breadth.

"At CeBIT it's not just about the latest technology but also about a social and political discussion on the relevant issues of digitalisation," he said.

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