It may be past its sell-by date, but for many Danes it's a tasty proposition: A supermarket in Copenhagen selling surplus food has proved to be so popular it recently opened a second store.

After launching in the gritty inner city district of Amager earlier this year, the "Wefood" project earlier this month drew a long line as it opened a second branch in Norrebro, a trendy neighbourhood popular with left-leaning academics and immigrants.

Hipsters rubbed shoulders with working class mums as a cooking school founded by Claus Meyer -- a co-founder of Copenhagen's celebrated Noma restaurant -- handed out cauliflower soup and bread made from surplus ingredients.

"It's awesome that instead of throwing things out they are choosing to sell it for money. You support a good cause," said Signe Skovgaard Sorensen, a student, after picking up a bottle of upscale olive oil for 20 kroner (2.7 euros, $2.9).

"Isn't it great?" pensioner Olga Fruerlund said, holding up a jar of sweets that she planned to give to her grandchildren for Christmas.

The sweets "can last for a hundred years because there is sugar in them," she added.

Selling expired food is legal in Denmark as long as it is clearly advertised and there is no immediate danger to consuming it.

"We look, we smell, we feel the product and see if it's still consumable," project leader Bassel Hmeidan said.

All products are donated by producers, import and export companies and local supermarkets, and are collected by Wefood's staff, all of whom are volunteers. The store's profit goes to charity.

Prices are around half of what they would be elsewhere, but even its biggest fans would struggle to do their weekly shop here.

The products available depend on what is available from donors, resulting in an eclectic mix that changes from day to day.

One weekday afternoon, customers were greeted by a mountain of Disney and Star Wars-branded popcorn, while the fresh fruit section had been reduced to a handful of rotting apples.

- Growing awareness -

Food waste has become an increasingly hot topic in recent years, with initiatives ranging from a French ban last year on destroying unsold food products, to a global network of cafes serving dishes with food destined for the scrap heap.

The Britain-based The Real Junk Food Project also opened the country's first food waste supermarket in a warehouse near Leeds in September.

With a greater focus than its Danish peer on feeding the poor, the British project urges customers to simply "pay as they feel".

A UN panel said earlier this month that supermarkets' preference for perfect looking produce and the use of arbitrary "best before" labels cause massive food waste that if reversed could feed the world's hungry.

Nearly 1.3 billion tonnes of food are wasted every year, more than enough to sustain the one billion people suffering from hunger globally, the United Nations' Food and Agriculture Organization (FAO) said.

Denmark has managed to reduce its food waste by 25 percent over the past five years, partly due to the influential "Stop Wasting Food" group founded by Russian-born activist Selina Juul in 2008.

Juul grew up in the 1980s Soviet Union and says she was shocked by the amount of food being thrown away in Denmark when she moved there as a 13 year old in 1993.

"Surplus food has become very popular," she said of one of the measures advocated by the group: offering heavy discounts on items that are about to expire, which is now done by most Danish supermarkets.

- Supermarkets changing -

Inspired by Juul, one of Denmark's biggest discount chains, Rema 1000, has become an unlikely champion in the battle against food waste.

Two of its main initiatives are about reducing waste after the product has been sold: The company stopped offering bulk discounts in 2008 so that single-person households would not buy more than they could eat.

Last year it reduced the size and price of some of its bread loaves for the same reason.

"The biggest problem with food waste is among the customers," said John Wagner, the chief executive of the Danish Grocers' Association.

Regular supermarkets were becoming better at forecasting demand for different products, but they needed to do more to inform their customers that a lot of food is edible beyond its expiry date.

Wefood next year plans to open in Aarhus, Denmark's second largest city, but Wagner said the brand was unlikely to become a major chain.

"The problem should be solved before we get to the point where we have to give the products to a store like Wefood," he said.