The United Nations Office on Drugs and Crime says the Afghan government must show results not just promises in combating drugs or financial assistance from states and international agencies will stop.
The head of the UNODC, Antonio Maria Costa, has just returned from Kabul where he met President Hamid Karzai.
The counter-narcotics chief told the Afghan president 2005 is critical for the new democracy and urged the government to give immediate support to the eradication of poppy fields, the source of heroin sold on the streets of Europe.
Failure to act now, he said, would lead to a loss of money from donor states, non-governmental organizations and other multilateral agencies.
The United States has pledged $780 million this year to help Afghanistan combat drugs with an emphasis on eradicating poppies. Non-government groups in Afghanistan recently urged the United States to reconsider its emphasis on eradicating poppy crops saying this could destabilize the country and devastate poor families.
But UN Drug Office Spokeswoman, Kathleen Millar, told VOA stability can only come if farmers stop drug cultivation.
"When you have 131,000 hectares of opium poppies there you have destabilization because essentially you have an economy that is being fueled by drug dollars and so you have an economy that's vulnerable to crime, organized crime, lawlessness, anarchy and an insecure democracy cannot take root in a drug culture," said Ms. Millar.
Ms. Millar says the way to prevent opium cultivation is to help farmers switch to alternative sources of income, supplement income losses and strengthen the criminal justice system.
The U.N. wants drug consumer countries, such as Germany and France, to issue international arrest warrants so that terrorists and drug traffickers can be brought to justice within Afghanistan.
Last year Afghanistan accounted for almost 90 percent of world opium production and the majority of heroin is consumed in European countries and Russia.