An Iranian policeman stands guard as 50 tonnes of illegal drugs are destroyed during a ceremony

Iran's parliament passed a long-awaited amendment to its drug trafficking laws on Sunday, raising the thresholds that can trigger capital punishment and potentially saving the lives of many on death row, local media reported.

The bill must still be approved by the conservative-dominated Guardian Council but gained parliamentary approval after months of debate, according to parliament's website and the ISNA news agency.