Afghanistan's interim government, headed by Hamid Karzai, has banned the cultivation of opium poppies, in a bid to stop drug trafficking.

A statement issued by the new administration said the ban included the trafficking of opium and all its derivatives, including heroin.

The decree renewed an order issued by the Taleban authorities two years ago, when Afghanistan was the world's largest producer of opium.

That ban was strictly enforced but since the fall of the Taleban, farmers in the main production areas have already been planting opium seeds for next year's crop.

UN incentives

Farmers ignoring the new order will face prosecution, according to the report.

"All countrymen, especially peasants and farmers, are informed that, from now on, the cultivation, manufacturing, processing, impermissible use, smuggling and trafficking of opium poppy and all its derivatives is declared illegal," the statement said.

The interim administration has asked the United Nations and the international community to help it provide incentives for farmers to grow food crops instead of poppies.

Under the Taleban ban opium production fell from more than 3,000 tonnes a year to less than 200 tonnes and the poppies were virtually eradicated from areas under their control.

Drugs stockpile

But desperate farmers in Nangarhar and Helmund have returned to growing the poppies.

UN drugs officials say that despite the drop in opium production Afghan farmers still have large stocks of opium and heroin that they can supply to the world market for the foreseeable future.

The BBC's Kabul correspondent Kate Clark says Afghan farmers may get only one percent of global profits from the opium trade, but that is significant money in such an impoverished country.