St John has confirmed two deaths believed to be related to a bad batch of synthetic drugs in Christchurch.
Over the last two weeks,19 people have been admitted to Christchurch Hospital suffering from "probable severe synthetic toxicity".
There have been no deaths from people admitted to hospital and two people remain in intensive care, the Canterbury DHB says.
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The two people who died over the last fortnight were not admitted to hospital.
Last week, emergency department doctors said the substance AMB-FUBINACA had been identified among analysis of patients' toxicology levels. The same substance, according to Christchurch Hospital, has been linked to numerous deaths during the past year in Northland.
In total, 45 users have died from synthetic drugs in the last 12 months.
St John and police will hold a press conference on the issue this afternoon.