Trafficking of the highly addictive stimulant methamphetamine in Afghanistan has surged in recent years, said a UN report published Sunday, indicating an expansion of the drug's production following the Taliban's crackdown on the opiate trade.

Afghanistan's Taliban rulers have clamped down on the decades-old, lucrative trade in poppy tar -- the psychoactive substance in heroin -- since surging back to power two years ago.

But while heroin trade has slowed, according to the United Nations Office on Drugs and Crime (UNODC), methamphetamine trafficking in and around Afghanistan has "intensified since the ban".

By monitoring drug busts in Afghanistan and neighbouring countries, UNODC has found a "drastic, nearly twelvefold increase in seizures of the drug in five years from 2.5 tons in 2017 to 29.7 tons in 2021", said a statement announcing the report.

The spike in seizures indicates an expansion in production of the drug, known as crystal meth, which can be easily manufactured in makeshift labs that are difficult to track, the report said.

Afghanistan has a natural source of ephedrines, a key ingredient or "precursor" for cooking meth, in the ephedra plant, which grows wild in the country.

But while ephedra is abundant in the region, the report underscored that meth production in Afghanistan likely did not rely on the plant alone, in part because of the challenges of harvesting it and the large amounts necessary to make one kilogram of the drug.

Between 6,500 and 11,700 tonnes of ephedra would be needed to make the 29.7 tonnes of meth seized in 2021 in and around Afghanistan, a country that produced an estimated 6,200 tonnes of opium in 2022, the report said.

Other sources of ephedrines are pharmaceuticals like cold medicine and bulk industrial-grade ephedrines, which are mass-produced in the region.

"Regional coordination targeting the diversion and smuggling of chemical precursors is essential to stopping the continued expansion of illicit methamphetamine manufacture in and around Afghanistan," said Ghada Waly, UNODC's executive director.

Taliban authorities could not be immediately reached for comment.

The government has moved to stamp out narcotic production, with Supreme Leader Hibatullah Akhundzada declaring poppy cultivation "strictly prohibited".

It was banned under the Taliban's last rule in the 1990s, but the export of heroin from Taliban-controlled areas provided the movement with millions of dollars during their insurgency against the United States and the Western-backed government.