A government study shows that the number of plastic bags distributed by registered retailers had dropped by 90 per cent after the levy was put in place.
However, the amount collected in the first nine months was less than HK$20 million, way lower than the estimate of HK$200 million for the first year.
Environmental group Greeners Action has also found that more people are taking plastic bags that are placed next to fruit and vegetable counters.
During checks at some supermarkets, it found 467 incidents of use of such bags.
'Supermarkets should keep these bags away from shoppers . . . and give them out only when necessary,' says Greeners Action project officer Kwok Ying-ying .
The group has also called on the government to expand the scheme from about 3,000 supermarkets, convenience stores, and health and beauty shops to smaller shops such as news-stands and dry-goods stores.