The government has allocated more than $1bln to "help strengthen the 8,000 kilometers in common border Iran has with its neighbors," Mohammad Najjar said on Thursday.
To counter drug trafficking, the Iranian government has deployed thousands of security personnel along its eastern borders and has built over 1,000 kilometers (620 miles) of embankments, canals, trenches, and cement walls.
"Drug trafficking, smuggling and the illegal entry of foreign nationals have caused problems in our borders," he added.
Najjar added that according to a report by the UN Office on Drugs and Crime (UNODC), the Afghanistan-Pakistan border region has become one of the world's largest free-trade zones for anything illicit, from drugs and weapons to illegal immigration.
During the last Iranian year (ended on March 20) Iran seized more than 1,000 tons of opium smuggled from Afghanistan.
Since the 1979 Islamic Revolution, the Iranian police have lost more than 3500 of their personnel in the country's combat against narcotics.
According to the statistical figures released by the UN, Iran ranks first among the world countries in preventing entry of drugs and decreasing demand for narcotics.
Each year, the government spends hundreds of millions of dollars erecting barriers along the borders with Pakistan and Afghanistan and pumping resources into checkpoints. Officials said the battle against drug addiction and trafficking costs Iran US$1 billion a year.