Drug dealers are flocking to Richmond to exploit a loophole that allows them to carry around 30 hits of heroin near the state's first injecting room, as local officers say they are powerless to stop them.

On Wednesday night more than a hundred residents attended an urgent meeting across the road from the Andrews government's injecting room to discuss their concerns, amid reports more than half of drug users in the area are shunning the centre to shoot up in public.

Richmond locals at this week's public meeting. Credit:Luis Ascui

Two police officers told The Age they have been instructed not to patrol the area around the facility, where they say people with the intention of using the injecting room are able to carry up to three grams of heroin without being arrested.

Possession and use of drugs in the injecting room is legal, meaning those who tell police they intend to use the facility are likely to be given a free pass to carry significant doses around the north Richmond area.