There has been a sharp decrease in poppy cultivation in Afghanistan, according to the latest UN report.
The report says cultivation in 2008 dropped 19% compared with last year.
But the UN Office on Drugs and Crime (UNODC) says the illegal drug trade continues to finance the Taleban and other anti-government insurgents.
Its head says that while the US and Britain are actively fighting the drug trade, other Nato nations like Italy are reluctant to do likewise.
'Flood waters recede'
"While Italy is saying no, the US and the UK are saying yes," UNODC Executive Director Antonio Maria Costa said.
"The situation will evolve and time will tell eventually what happens.
"My understanding at the moment is that the countries which have decided to intervene are organising themselves to do just that."
The BBC's Rob Watson says that the decrease in poppy production is a rare piece of good news from Afghanistan.
"The opium flood waters there have started to recede," the UNODC report said.
The survey showed that over half of the country's provinces are now poppy-free and the production of opium has declined by 6% since last year.
It shows the price of opium has plummeted and that illegal drugs are now less important to the country's economy.
The UN credits the improvement on strong local leadership, last year's drought and improved prices for legal crops such as wheat.
But our correspondent says that to some extent the problem has merely been concentrated in the south of the country, with Helmand province now accounting for almost two-thirds of Afghanistan's opium production.
The UN says the Taleban and other insurgents are still making massive amounts of money from the drugs trade despite the drop in prices and cultivation.
It has accused the Taleban of trying to manipulate the market by holding secret stocks of opium in an effort to drive up world prices.
It says that the answer to the drug problem remains the same: more honest government, better development and security assistance from the international community.