The report, 'A Recipe for Disaster', claims that supermarkets continue to source seafood with little consideration for the sustainability of the fish stocks they sell, jeopardising the stability of worldwide marine ecosystems.
Asda, the UK's second largest retailer, comes bottom of the league of all nine retailers surveyed. It scored just one out of 20.
US-owned Asda sells at least 13 species on the Greenpeace endangered list, including swordfish, dogfish and Atlantic cod, and has the worst record for labelling and sourcing.
An Asda spokesperson told FoodandDrinkEurope.com: "We're disappointed that Greenpeace has singled us out. We've met them time and again recently to explain that our approach to sourcing fish is no different to that of our competitors."
She says the Greenpeace message is confusing, and claims the environmental advice on the campaigner's website, telling consumers to stop eating fish and replace it with walnuts, is quite literally nuts.
"Our customers don't want nut-fingers and chips for their tea. That is why we will continue to sell a full range of fresh fish in all stores - whilst ensuring it is sourced from the most sustainable places possible," she said.
But the Greenpeace report states that three quarters of commercially valuable fish stocks are already fully exploited, overexploited or depleted, and supermarkets must play a more active role in marine protection initiatives.
The UK seafood retail market is worth £1.8 billion a year, and with nearly 90 per cent of sales made through supermarkets, retailers hold huge sway.
"We had a good hunch that some supermarkets were not selling sustainable seafood stocks but when we actually looked into it, it was quite staggering that some big players like Asda are so far behind," said Greenpeace campaigner Oliver Knowles.
However Marks and Spencer topped the league, scoring 17, and was found to have the most comprehensive and progressive fish policy, according to Knowles.
And Waitrose, who was also praised for its purchasing policy, came in second with 15 points. Sainsbury's ranked in third place with 10 points.
"It was a pleasant surprise to discover that some of the leading supermarkets like Marks and Spencer and Waitrose are really taking the issue seriously, but more should be done," said Knowles.
The Greenpeace report adds weight to environmentalists' claims that Britain needs an all-encompassing Marine Bill to protect fish stocks from destruction.
The World Wildlife Fund for Nature (WWF) has been in consultation with the Marine Conservation Society, local MPs and the Department for Environment, Food and Rural Affairs (Defra) to push for protective legislation - which may make fish sourcing a real issue for retailers in the future.
Defra has tentatively started the initial consultation process for the introduction of a restrictive Marine Bill, but says it may be as late as November 2007 before the Act can be introduced.
Meanwhile, fish populations in British waters are at an all-time low. And according to Greenpeace even the nation's fish-n-chip favourites are under threat - that includes the ubiquitous cod, haddock and whiting.