There is light at hand for those who toil away in a poorly-lit office. Scientists at the CeBIT high-tech fair have developed a system that gives the feeling of working outside under blue skies.

The system, called "virtual sky", uses large flat-screen ceiling panels with 288 tiny light-emitting diodes (LEDs) that can each produce red, blue, green and white -- giving a total of 16 million colour combinations.

The LEDs can also create moving shapes, such as clouds, and reflect the changing light of the day, including sunrises and sunsets, depending on the time.

The effect is that when you look up from your desk, you feel as if you are gazing into a bright spring sky with small billowing clouds passing slowly by.

Studies have shown that the feeling of space dramatically improves workers' productivity, explained Matthias Bues, the scientist at the Fraunhofer Institute who designed the new system.

"It really makes you feel like you are outside," he told AFP.

"Light is so important to your sense of well-being and people love the feeling that they are not actually in the office," he added.

He said that interest had flooded in since announcing the launch of the new system at this year's CeBIT, the world's biggest high-tech fair in the northern German city of Hanover.

"We have had very strong interest from several companies. Make no mistake, you will be seeing this in real offices very soon," he predicted.

He added there had also been interest from hospitals and nursing homes. "It can be extremely therapeutic for people who cannot go outside very often" such as the elderly, infirm or handicapped.

And as "virtual sky" uses LEDs rather than fluorescent strips, it is also more environmentally friendly than most current lighting systems.

The panels, measuring 50 square centimetres (eight square inches) cost around 1,200 euros ($1,600) each.

The CeBIT, which runs until March 10, this year welcomes around 4,200 exhibitors showcasing the inventions of the future, from tech behemoths such as Microsoft and Google to one-man-bands with a quirky gadget.