Leading supermarkets in the UK are still using too much packaging, with up to about 40% of it unable to be recycled, a report has suggested.
Supermarkets say they are trying to improve packaging.
The study, by the Local Government Association, warns that Britain will miss recycling targets if big chains do not cut back on packaging.
Its report, which looked at a basket of 29 common grocery items, found that Lidl products had the most packaging.
And Marks and Spencer (M&S) used the most non-recyclable materials.
Asda, Morrisons, Sainsbury's, Tesco, a local retailer and a market were also included in the study.
An average of 5% of the total weight of the products bought for the study was made up of packaging, the LGA said.
And the local market and a local retailer had the most packaging which could be recycled - both at 79%. This compared with just 60% at M&S.
Chairman of the LGA's environment board, Councillor Paul Bettison, said that the public were working hard to increase the amount of recycling that they did, but that retailers were not always making things easy.
"Their efforts are being hamstrung by needlessly over-packaged products on sale in supermarkets," he said.
HOW MUCH PACKAGING COULD BE RECYCLED?*
Local market - 79%
Local retailer - 79%
Asda - 70%
Sainsbury's - 70%
Morrisons - 68%
Tesco - 62%
Lidl - 61%
M&S - 60%
Based on sample of 29 items Source: LGA
"We have to question the necessity and desirability of shrink wrapping vegetables like peppers and broccoli."
Head of corporate social responsibility at M&S, Mike Barry, said that the firm had set clear targets to reduce its packaging and to only use materials that could be easily recycled or composted.
"While we've made good progress over the last 12 months, we know there's still much more yet to do in both areas," he said.
"Almost 70% of our packaging is recyclable across the majority of local authorities.
"A further 20% could also be recycled if there was a more consistent approach to recycling across the UK. We're working with local authorities to help address this."
A separate report, published last week by the National Consumer Council (NCC) said that UK supermarkets had gone "greener", but still needed to do more to help customers reduce their environmental impact.
The NCC said chains must further cut plastic bag use and recycle packaging.
They were also urged to increase the amount of organic and locally-sourced food on their shelves.