Osaka University professor Hiroshi Ishiguro displays the world's first news reading humanoid robot "Kodomoroid" in Tokyo. A future in which it is difficult to tell man and machine apart could soon become reality, scientists say, after recent robotic breakthroughs in Japan. Yoshikazu Tsuno / AFP

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A future in which it is difficult to tell man and machine apart could soon become reality, scientists say, after recent robotic breakthroughs in Japan.

Wise-cracking android sidekicks, a once-fantastical idea, are taking form in laboratories. As the gap between humans and robots narrows - society faces ethical and legal complications as yet undreamed of, they warn.

"Already computers have surpassed human ability," leading Japanese roboticist Hiroshi Ishiguro says. "Robots will be very clever soon."

Science fiction's rapid slide toward science fact owes much to the likes of Ishiguro, who has an android copy of himself that he sends on overseas business trips in his place.

"It saves me time," he smiles. "The upper torso and lower torso you can pack in two big suitcases. The head is very fragile - it goes as carry-on baggage."

Robots already perform a wide variety of tasks in Japan: They cook noodles, help patients undergo physiotherapy and have been used in the cleanup after the 2011 nuclear meltdown at Fukushima.