For the chemicals used to turn opium into heroin come in from other countries, she told reporters on Monday.
"You often hear that Afghanistan is the root for all the evils in terms of drugs problems in the world, but I think this is wrong," she said.
Afghanistan produces more than 93 per cent of the world's opium and UNODC estimates that 60 per cent of it was last year turned into heroin inside the country. All the chemicals for this process are smuggled into Afghanistan.
"These chemicals originate from China, South Korea, the Russian Federation, Europe and some other countries," Oguz said.
The UNODC estimates that about 13,000 tons of chemicals are required for the amount of heroin produced in Afghanistan, with opium output at about 8,200 tons.
The chemicals are produced legally for industrial purposes in other nations.
"In most cases they are also legally exported, but once they reach the destination point they are diverted and then smuggled into Afghanistan," Oguz said.
The chemicals often arrive via Pakistan, Iran and some other neighbouring countries, she said.
Afghanistan's opium production has grown steadily since Taliban were removed from government in late 2001 in a US-led invasion and despite the costly efforts of the country's international allies, notably Britain and the United States.
Most of the heroin in Europe comes from Afghanistan.
Work to slash drug production has taken on new urgency amid claims that Taliban-linked insurgents are taking a cut from the illicit trade, with some government officials also benefiting.
Oguz alleged that powerful drug-lords were managing to escape justice merely by making a telephone call to senior authorities in the Afghan government.