Eleven people have been hospitalised in Wellington in the past week and a half following suspected synthetic drug use.
Four people were urgently admitted to hospital in the space of 24 hours in Porirua, but Capital and Coast DHB has now revealed the number of affected patients so far this month is more than double that.
"In the past week and a half, 11 people have come to Wellington Regional Hospital's emergency department experiencing the effects of what doctors believe to be synthetic drugs," a statement from the DHB said.
"Of those people, at least five were admitted to hospital between 7 and 8 November."
Kapiti-Mana Police said emergency services were called four times between Tuesday and Wednesday afternoon.
Detective Senior Sergeant Grant Ferguson said each patient was believed to be affected by synthetic drugs.
He urged anyone using drugs to stop immediately and contact their GP or the Alcohol Drug Helpline for help.
"We also ask members of our community who may think someone has taken synthetic drugs to call 111 immediately and seek medical assistance for them."
In September three Porirua children had to be rushed to Wellington Hospital after apparently eating synthetic cannabis with their dinner.
The children, aged 5, 8, and 14, were all from the same family.
The 8-year-old boy was in an "almost comatose" state and had to be put in an induced coma for several days.
At the time Ferguson said the case highlighted the "absolute risk" people were taking by using synthetic drugs.
"I just wish people would listen to the warnings being given, because we've had too many deaths lately.
"The message is not getting through. This is fatal stuff.
"People need to leave this stuff alone. It's killing people up and down the country."
Police and the chief coroner have confirmed 20 people have died so far this year as a result of suspected synthetic drug use.