The NATO-led force in Afghanistan said Monday it had made "incredible" seizures of drugs in Afghanistan last year and dealt a blow to the finances of the Taliban-led insurgents.

"Narcotics trafficking has been a key generator of funding for the insurgency, but that source of revenue is diminishing," Brigadier General Carsten Jacobson, spokesman for the International Security Assistance Force, told a news conference.

"Afghan security forces, together with ISAF partners, seized an incredible amount of illicit drugs and related material in 2011 versus 2010."

Opium seizures rose 13 percent and those of hashish climbed 59 percent, while the amount of marijuana and morphine confiscated soared 1,208 percent and 10,113 percent respectively, according to the figures from ISAF, which did not give the amounts of drugs seized.

"Counter-narcotics operations are successfully disrupting the insurgents' ability to process opium into heroin. We will continue to choke off revenue generated by the sale of illicit drugs in 2012," Jacobson said.

ISAF's optimism is in stark contrast to the UN Office on Drugs and Crime (UNODC), which in October said opium production in Afghanistan rose 61 percent in 2011 from the previous year, when the harvest was hit by disease.

The UNODC estimates this year's output at 5,800 tonnes against 3,600 tonnes last year, with a slight increase in area under poppy cultivation to about 13,1000 hectares (324,000 acres) in 2011.

After a slight decrease in 2010, Afghanistan will again be responsible for 90 percent of the global opium production, with 78 percent of the total coming from the troubled south, the UNODC said.

According to UNODC country head Jean-Luc Lemahieu, this year opium will generate about $700 million for the Taliban, who have been fighting a decade-long insurgency against the Afghan government and its NATO-led ISAF allies, and several billion dollars for criminal syndicates while also fuelling corruption in the country.

"We will continue to defeat them on the battlefield and we will continue to take their revenue away wherever we can," Jacobson told AFP.

"An insurgency is never defeated in one field alone. An insurgency can only be defeated by efforts all across the board, that is their fighters in the field, the money that they finance themselves with, the political process that brings stability and governance to the regions of Afghanistan."

"Once this process becomes so overwhelming that the insurgents cannot to anything against it anymore, the insurgency will dry out."

In December, Afghanistan and its seven neighbours launched a programme to cooperate in the fight against drug trafficking.