Urban Development Corporation, a government-affiliated body that provides public housing, said Wednesday it will begin an experiment in March 2002 allowing residents to keep small pets at a rental apartment complex in Tokyo's Koto Ward.

In most apartment complexes in Japan, keeping cats, dogs, birds, rabbits, hamsters or other small animals is prohibited due to the limited space and the possibility that noisy pets might upset neighbors.

But the country's rapidly aging society has prompted the UDC to experiment with allowing residents to keep pets in a bid to provide comfort and reduce stress among the growing legions of elderly urban residents, officials said.

Each of the 145 apartments in the 11-story building will be equipped with sound-proof windows, easily replaceable wallpaper, a door with a built-in pet door and other facilities to make it easier for residents to keep pets, the corporation said.

More rental apartments of this sort might be built if the experiment, which will continue for at least for a year, goes well, officials said.