Japanese car giant Toyota on Wednesday unveiled a robotic best friend that can offer a helping hand around the house fetching and carrying for the elderly or immobile.

The human support robot, a compact cylinder-shaped machine 37 centimetres (about 15 inches) in diameter and up to 130 centimetres tall, can be remotely controlled by a tablet computer to recognise items it is sent to fetch.

Taking their cue from dogs that are trained to retrieve things, Toyota engineers designed the robot to perform simple tasks on command, using an arm equipped with a small suction pad.

"The robot still has challenges such as selecting items from a drawer containing all sorts of things, for example," said Takashi Yamamoto, general manager at Toyota's advanced technology engineering department.

"Finding an item by itself before getting it to the person controlling it is the most difficult challenge," he said.

Toyota, one of the world's biggest automakers, has applied technology developed for its cars, such as precise control of motors at high speeds, in the design of the robots.

Products catering to the elderly are big business in Japan, where a declining birthrate and lengthening life-expectancy is creating a greying society.