Another supermarket chain, China Resources Vanguard, has pledged to reduce distribution of plastic shopping bags. This is the third voluntary agreement signed after similar agreements with Wellcome and PARKnSHOP in February and March.

It pledged to plastic bag distribution at its retail outlets by at least 15% in one year.

Permanent Secretary for the Environment, Transport & Works Keith Kwok said the Government is pleased to see the three major supermarket chains are committed to reducing plastic bags by about 90 million in a year.

"We are also encouraging other supermarkets and major retail chains to join the voluntary scheme," Mr Kwok said.

The active involvement of supermarket chains will help change consumer behaviour over time, he said, adding a large number of plastic shopping bags are disposed of at landfills each day. He said the implementation of voluntary agreements will reduce this kind of waste at the source.

In the longer term, the Government plans to prohibit free distribution of plastic bags and impose a levy to deter their use through legislation. It will consult the trade and the public before taking it forward.