Greeners Action recruited nine people and sent them to supermarkets 33 times between June 16 and 23 to buy products with plastic packaging.
They ended up buying 276 plastic-packaged items, including 63 holding 52 types of fruit and vegetables.
Also encased in plastic were products including meat and frozen food items, snacks, beverages, seasonings, oil, grains and sanitary products.
A woman, Yan, said a mango she bought came with polyfoam wrap, plastic wrap and then a plastic box.
"The packaging is excessive and pushes up prices," she said.
Several shoppers found undersides of fruit to be rotten after they removed packaging.
But shopper Mui said excessive packaging made it difficult to check products.
"I bought a pack of strawberries but couldn't check whether they were fresh as they had two layers of packaging," she said. "After I removed it I found some strawberries in the center were rotten."
Some customers also believe supermarkets use more packaging to bundle products before they spoil.
A woman, Lau, said she wanted to buy one tomato in a supermarket but could only find quantities in packaging.
She also tried to buy a green pepper for juice "but all I could find in the supermarket were green, yellow and red peppers bundled together."
Some customers also found foam particles on vegetables and worried they could have ingested some previously.
Greeners Action executive director Angus Ho Hon-wai said the overpackaging hinders consumer choice.
Supermarkets, he said, use disposable packaging materials "to make products look posher, but it is actually product bundling, making customers buy more and pay more and causing waste."
He said the SAR's two largest chains - Wellcome and ParknShop - should bear responsibility for environmental protection, which could include setting up zones for products without plastic wrapping and reducing overpackaged fruit and vegetables.
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