The United Nations says it fears that Afghanistan may grow even more poppies in 2007 - at a time when current levels are already running at record output.
Poppy production was up 25% in 2006, the US has said
Poppy production rose 25% in 2006, according to the US State Department.
The UN says although production of poppies, used to make heroin, has fallen in the north and centre, a sharp rise is likely in the lawless south.
It also cites a dramatic increase in cannabis growing, which it describes as a new and disturbing trend.
In a report published on Monday, the UN office on drugs and crime said it was clear that the increased production in the south was a security issue.
'Cancer of insurgency'
Many southern regions have no government presence, while opium farmers were protected by the Taleban which uses drugs money to fund its insurgency, it said.
"It is clear that the insurgents are deriving an income, which they use to pay salaries for their foot soldiers (and) to buy weapons," said Antonio Maria Costa, the UN department's executive director.
"All of this has created quite a cancer of insurgency and illicit drug cultivation that has to be cut through in the years to come," he said.
He said the eradication effort needed to be increased to be effective. Last year, about 10% of the crop was eradicated, but Mr Costa said the figure should rise to 30%.
Four years after the US and its British allies began combating poppy production, Afghanistan still accounts for 90% of the world's opium trade.