Norway and Sweden are locked in a tug-of-war over dozens of lorries that cross the border each day carrying loads of precious cargo: garbage.

Sweden is conscientious when it comes to sorting and recycling its waste and is in the rare position of lacking garbage for its incineration centres, which produce enough electricity for 250,000 homes and heat for 950,000 homes.

As a result, it has to import around two million tonnes of waste per year, primarily from neighbouring Norway but also from Britain, the Netherlands, Finland, Denmark and Ireland.

"It's like a market," Weine Wiqvist, head of the Swedish Waste Management and Recycling Association which represents the industry, explains to AFP.

"Transporting waste from countries to other countries is a business driven by the balance of supply and demand."

It is however an atypical market where the exporters (municipalities and industries) pay the importers (incineration companies) to burn their "products".

Incineration companies have popped up like mushrooms in Sweden in recent years, pushing fees down, which has enticed Norwegian municipalities with strained budgets to look across the border to get rid of their waste.

This has led to some absurd situations.

The municipality of Voss on Norway's west coast sends its waste to Jonkoping, around 800 kilometres (500 miles) away in central Sweden, even though there is an incineration centre in Bergen just 100 kilometres away.

Norwegian industry officials accuse their Swedish counterparts of dumping prices, preventing not only their nascent industry from growing but also hindering efforts to develop an eco-friendly district heating network.

"Beer and tobacco aren't the only things that are cheaper in Sweden. Waste management is also cheaper over there," says Odd Terje Dovik, the head of the Returkraft incineration centre in the southern Norwegian town of Kristiansand.

"The Norwegian centres that could have burned this waste have to in turn import from Britain," he adds.

- 'Wasted waste' -

The transportation of the waste has an environmental cost, although the Swedes defend their practice.

"There have been a lot of calculations and research on this. And they found out that the transportation itself is almost negligible," insists Wiqvist.

"It's very little compared to the savings you make when you take waste away from a country -- where it would otherwise have been landfilled -- and you use it as a fuel because when you use it as a fuel, you replace other fuels like coal or natural gas," he adds.

Three tonnes of waste provide the energy equivalent of one tonne of petrol or two tonnes of coal, according to Sweden's waste management association.

While landfill methane emissions -- one of the worst greenhouse gases -- pose a real threat to the climate, Norway insists that the argument does not hold water since it, contrary to Britain for example, banned landfills in 2009.

"It has become so advantageous to burn waste in Sweden that the incentive to sort and recycle in Norway is eroding, so much so that the statistics are going in the wrong direction," lamented Dovik.

According to official figures, the recycling rate of Norwegian household waste (reuse, composting and biogas production) dropped last year to 37 percent from 44 percent six years earlier.

"The environment stands to gain a lot if the Swedish incineration centres went to pick up their waste in Eastern Europe, where the only alternative is landfills, rather than in Norway," Dovik says.

Despite a European Union directive aimed at limiting the volumes of waste sent to landfills by 2025, more than 100 million tonnes are still being dumped every year.

"A lot of waste is being wasted in Europe," notes Helge Ziolkowski of the Swedish Environmental Protection Agency.