Christchurch streets are said to be rife with synthetic cannabis, made of a hodgepodge of poisons

A Coroner's ruled the substance contributed to the death of a Christchurch mental health inpatient in 2018.

City Missioner Matthew Mark says synthetics users are still walking through the mission's doors - but the batches in the community are higher-risk.

He says the widely-available substance is manufactured from hideous ingredients - including rat bait, antifreeze and cleaning fluid.