In a new report, the agency says the programme would mean clean needles and syringes for users, but would also involve counselling, testing and vaccination.
"There is no point letting addicts catch a load of other diseases and think it will help them get out of their addiction. It's actually the other way around. It will lead to a downward spiral," the agency's general director, Johan Carlson, told news agency TT.
Needle exchange programmes are controversial in Sweden, with politicians in many areas saying no to the plans. At the moment, exchange programmes are only available in six counties, including in the capital city, Stockholm and in Malmö, Sweden's third largest city.