Hong Kong's Environmental Protection Department has said a 50-cent levy could cut plastic bag use in Hong Kong by a billion.

In a proposal given to lawmakers, the department said over eight billion plastic shopping bags are disposed of at landfills annually, which is more than three bags a person each day, and this is much higher than figures for developed economies overseas.

In an opinion survey on bag usage conducted last year, local media reports that more than 85% of respondents said they will cut usage if a levy is imposed. The result of the No Plastic Bag Day campaign indicates that a voluntary charge of 50 cents could lead to a drop in plastic shopping bag usage by up to 54% at participating retail chains.

The department suggests adopting a phased approach in imposing the levy by first covering chain or large supermarkets, convenience stores and personal health and beauty stores, affecting up to 100 retailers with about 2,000 outlets.

The levy will apply to bags made wholly or predominantly of plastic, and have carrying handles, holes or strings. Bags with no handles, holes or strings; sealed bags applied before goods are offered for sale and bags sold as packaging materials or liners, will not be subject to the scheme. Reusable shopping bags sold for or more each will also be exempted.

It estimated that the levy collected for the first few years will be less than HKD200 million a year. The department hopes to consult the public and discuss the implementation details with the trade in the next two months and expects to formally implement the levy from the end of August next year.