President Hamid Karzai has called for more international help to fight drug production in Afghanistan.
The Afghan government is hoping to wean farmers off poppy crops
Speaking at a major aid conference in Berlin, he said drugs were undermining the "very existence" of his country.
Afghanistan is the world's biggest producer of poppy-derived opium, which is used to make heroin.
The two-day Berlin conference, attended by officials from 50 countries, is considering fresh aid to Kabul - which is seeking $27.5bn over seven years.
German Chancellor Gerhard Schroeder, the host, urged the world to "stress its commitment to a secure, free and democratic Afghanistan".
The UN has warned Afghanistan is in danger of becoming entirely dependent on the illegal drugs trade and reverting to chaos unless it receives sufficient foreign aid.
Mr Karzai urged the world community to help destroy opium plantations and find alternative crops for farmers.
He said the problem was "too huge" for his country to face alone.
"Afghanistan's agriculture, Afghanistan's economy, Afghanistan's
way of life, Afghanistan's tradition and culture is being threatened
by drugs," he said at the conference.
One of the world's poorest countries, Afghanistan remains a security concern for Western countries, two years after US-led forced ousted the Taleban.
Much of the country is controlled by warlords and drug production - estimated at $2.3bn in 2003 by the United Nations- is rising.
The BBC's Andrew North says that an opium farmer may be earning 10 times as much as the government soldier or policeman whose job it is to enforce the law against growing the crop.
The Berlin conference follows a first donor conference held in Japan in 2002 and will consider a report submitted by the Afghan government and institutions like the World Bank.
The World Bank's country director for Afghanistan, Alastair McKechnie, has defended the amount of development aid being sought by Kabul.
He put the total cost of two decades of war at about $240bn.
"The figure of $27.5bn may seem a lot but it will simply help Afghanistan get back on the track from which its people were brutally wrenched in the late seventies," he said.
Afghan Finance Minister Ashraf Ghani said that new investment would nurture the hope of peace whilst international neglect would spell "dire consequences" for both Afghanistan and the region.
"We are not asking for the Mercedes Benz (of development
assistance programmes) - we are asking for a bicycle," Mr Ghani told delegates.
There have also been serious outbreaks of fighting in various parts of the country, with the central government controlling only the capital.
The Afghan government has been forced to delay presidential and parliamentary elections scheduled for June until September because of security concerns and problems with voter registration.