More than 100 discarded needles were found in Newport in one day.
Volunteers collected a total of around 150 needles from two different areas in the city on Saturday 11.
They also collected a number of metal spoons, wipes and packaging.
The needles were found during a routine litter pick organised by community group Pride in Pill after they were alerted to the issue by a nearby pub owner.
70 needles were found in a lane next to the Carpenters Arms near High Street whilst another 80 were discovered near the former Sainsbury's site in Shaftesbury.
Paul Murphy has run the voluntary group Pride in Pill since 2014. They regularly organise litter picking events and help the homeless in Newport.
The 48-year-old, who works full time as a cleaner, said he and other volunteers have been trained to dispose of sharps safely and the group regularly pick up replacement equipment from a local needle exchange.
The group plan to make trips over the coming days after they received reports of other areas where the problem persists.
Keep Wales Tidy recommend reporting any drug-related litter to your local authority instead of attempting to pick it up yourself.