The UN has warned that Afghanistan could become a "narco-state" after opium cultivation rose by two-thirds this year.
A UN report released on Thursday urged the US and Nato forces to fight drugs as well as Taleban insurgents.
It said Afghanistan now supplied 87% of world opium. In 2003, the trade was worth $2.8bn, representing more than 60% of gross domestic product.
One in 10 Afghans are now estimated to be involved in the business.
The UN said it would be an "historical error" to abandon the nation to opium.
'No silver bullet'
The UN Afghanistan Opium Survey 2004 said the drug was now the "main engine of economic growth and the strongest bond among previously quarrelsome peoples".
Afghan opium production graph
It said opium cultivation had increased by 64% compared to 2003.
Antonio Maria Costa, executive director of the UN Office on Drugs and Crime, said the report was a wake-up call to the world.
Mr Costa said the Afghan government was too weak to tackle the problem alone.
He called on US and Nato-led forces to carry out military operations against drug traffickers.
"In Afghanistan, drugs are now a clear and present danger," Mr Costa said.
"The fear that Afghanistan might degenerate into a narco-state is becoming a reality."
He said there was "no silver bullet" with which to tackle the problem.
"The opium economy in Afghanistan has to be dismantled with democracy, the rule of law and economic improvement - it will be a long and difficult process," Mr Costa said.
The UN report said opium production in 2004 was close to the peak of 4,600 tons in 1999, a year before the Taleban banned new cultivation.
The BBC's Roland Buerk in Kabul says it is easy to see why 2.3m people - a tenth of the population - is involved in opium, when a farmer can earn more than 10 times as much growing poppies than cultivating wheat.
US prosecutions
The report came as the US announced a major new offensive against drug production in Afghanistan.
Washington expects to spend an extra $780m in the next financial year on measures including the eradication of poppies and alternatives for farmers.
US officials describe the new plan as a full-board commitment to support the new Afghan government in its battle against the growing drugs trade.
A senior Western diplomat in Kabul also told the BBC there were plans to take some of the largest drugs barons to the United States to prosecute them there.
Robert Charles, assistant secretary of state for International Narcotics and Law Enforcement, described poppy cultivation as a primary, if not the primary, concern for the country.
Aggressive eradication would be backed up, Mr Charles said, by a public information campaign, better law enforcement and, perhaps most crucially, real alternatives for farmers.
"You don't go in and eradicate in an area without making provision... for a marked up or added alternative development resources, or alternative livelihoods," he said.
