The replacement of humans by machines in the workplace took another step on Wednesday, as Japanese researchers unveiled a model they hope could lead to humanoid menial workers.

Its makers, Kawada Industries and the National Institute of Advanced Industrial Science and Technology (AIST), hope the robot will be a step towards creating a model that can help ease greying Japan's looming labour shortage.

"We designed a working robot in the image of a lean but well-muscled track-and-field athlete," Noriyuki Kanehira, robotic systems manager at Kawada, told a news conference to unveil the blue-and-white "HRP-4."