Shoppers in a Tokyo suburb are being threatened with a shopping bag tax by an environmentally-aware authority.

Officials in the city's Suginami Ward want a 5 yen tax imposed on each petroleum-based plastic shopping bag used in the ward's stores and supermarkets in a bid to reduce the amount of rubbish generated.

They claim the estimated 400 million yen revenue generated by the new tax could then be used to help protect the environment through activities such as the preservation of old trees.

The proposals will be discussed at a later date.