For diners in Tokyo — the city crowned recently by Michelin as the gourmet capital of the world — the near future will present an etiquette dilemma: should you tip a robot waiter? And, if so, with what?

Aro, which proudly calls itself a multifunction “concierge robot”, offers impeccable service. It is unfailingly polite, immaculately turned out in a pink waistcoat and bow-tie and armed with some inspired menu suggestions.

In a nearby booth at the Tokyo International Robot Exhibition, the Kokoro Company’s super-realistic Simroid reclines on a dentist’s chair, its mouth wide open and eyes flicking nervously to left and right. Student dentists are encouraged to practise their techniques on its ultra-sensitive robot canines and molars: if they hit too close to a nerve, it winces and shrieks. The Simroid’s breasts are even equipped with an “inappropriateness” sensor that detects if the trainee dentist is attempting anything untoward with his non-drilling hand.

A few yards away is a working model of the Lady Bird, a £15,000 robot that in two years will begin cleaning the notoriously vile lavatories of motorway service stations across Japan.

The robots are the products of a country running dangerously short of children and the workers of tomorrow. The low birthrate in Japan has been a persistent worry, and by 2030 the workforce will have shrunk by nearly 11 million people, the Government announced yesterday. To meet the shortfall Japan would need to take in 500,000 foreign workers every year between now and then.

In 2005 it admitted 20,000 and shows little sign of opening its doors to mass immigration. It is this dire demographic outlook that has led to a frenzy of investment in machines that could replace humans.

Industrial robots, of the sort that are behind the Japanese manufacturing “miracle”, remain a focus of vast funding. Now, robots are moving into roles that have only ever been performed by people.

The carmaker Subaru has released one that cleans offices after hours and can take the lifts to attend to every floor. “Our main objective,” a Subaru spokesman said, “is to deal with the shortage in the labour force that has arisen from the low birthrate. Robots do the ‘D-work’ — dirty, dangerous and difficult — jobs that Japanese shy away from.”

Other robots on display were designed with similar concerns in mind. The Fujitsu Enon is built to work the reception desks of large offices, leading visitors to meeting rooms and carrying parcels and boxes. Alsok, meanwhile, was showing off a robot security guard built to patrol the same type of office after hours.

Coming soon

Steps Honda has a humanoid that can run up stairs

Exercise The National Institute of Advanced Industrial Science and Technology has designed a robot that can demonstrate exercises

Guide Hitachi has a robot that uses sophisticated radar to lead visitors through crowds to their destination

Safety Taisei has a robot that will enter a building and remove asbestos by remote control

Nurse The University of Shiga is close to perfecting a robot that lifts people from beds into wheelchairs. The Riken Research Institute is developing an endoscopic surgery robot that follows voice commands to pass instruments to the human surgeon

Words The National Institute of Information and Communications Technology has a robot capable of learning sign language. Tokyo University of Science has built one capable of reproducing mouth movements and should, researchers say, soon be able to mimic human speech

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