Limits on the number of dogs and cats that can be kept by breeders and pet shops to ensure animals are properly cared for were discussed Friday by an Environment Ministry study group.

Under the plan, a breeder could look after up to 15 dogs or 25 cats, while a pet shop employee could care for 20 dogs or 30 cats. The difference in limits reflects the extra time a breeder needs to devote.

A store clerk at a pet shop in Tokyo holds a dog and cat on Dec. 22, 2017. An industry body said the estimated number of pet cats in 2017 has topped that of dogs for the first time in Japan. (Kyodo)

The ministry also proposed no breeding beyond the age of 6 amid concern the current practice of forcing aging animals to reproduce is inhumane. Exceptions will be made for dogs that have given birth up to five times, and cats nine times, in which case the breeding age limit will be 7 years old.

To address concerns about abusive breeders and pet shops that keep animals in confined spaces, the ministry wants cage sizes at least 1.5 times to triple their size, and to secure exercise space alongside exercise time of more than three hours.

Animal management licenses will be revoked for repeat offenders who do not follow regulations.

The group will finalize its plans by summer with new regulations expected to be in force next year, part of a ministerial ordinance under the revised animal protection law.

Environment Minister Shinjiro Koizumi told a press conference Friday the specific regulations are aimed at "ensuring health and safety of animals."

Japan amended the animal protection law in June last year to ensure humane treatment of pets, but it lacks specific regulations against abusive breeders and the pet shop industry, making it hard for local authorities to crack down.

The revised law, effective June 2021, bans the sale of dogs and cats under 56 days old, as experts have pointed out animals separated from their mother early in life tend to bite more and develop other problems.

It also obliges pet shops and breeders to insert microchips in their pets by June 2022, to reduce the number of strays.