Thirty-one people have now been admitted to Christchurch Hospital since the first reports of people suffering the effects of synthetic drugs three weeks ago.
In the last week, 12 more patients have been admitted to hospital after smoking the drugs, bringing the total number of people hospitalised to 31 since September 20.
Two of the first three people admitted remain in intensive care, the Canterbury District Health Board confirmed to Newshub.
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Last week, St John confirmed to Newshub two people have died, believed to be due to a bad batch of synthetic drugs in Christchurch.
There have been no deaths from people admitted to hospital. The two people who died were not admitted to hospital.
In September, 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.
A Coroner's report in June linked the drugs to as many as 45 deaths in a year compared with two deaths in the previous five years.