St John says they often get multiple call outs for single patients who have taken synthetic cannabis.
They say paramedics arrive to treat the person high on synthetic drugs, but they stir awake, walk around the corner and then light up again.
Newshub followed St John for a day as they dealt with people who'd taken the drug.
At 2pm on a Thursday, they're called to a commercial property in Grey Lynn.
Down the driveway is a man and a woman, one nearly unconscious on the ground and the other slumped over a bin.
Both are incoherent, and can barely keep their eyes open, or hold themselves up.
St John territory manager Blake Murray says: "They've said they've had synthetics so that'll 100 percent be what it is. It's pretty bad aye."
But after about 20 minutes, and a few medical checks the effect of the drug starts to wear off.
"Very often they'll either wake up fairly early on in our arrival or they'll be awake by the time we get there but they can usually be in quite a dazed and confused state and sometimes tend to be violent," says Mr Murray.
We find out both patients are rough sleepers, an all too familiar callout for emergency crews.
A couple of hours later we see the same patients sitting on a bench in Queen St. It's one of the many hotspots across the CBD. Another is High St, and not far from there on Elliot St.
"It does appear that there has been a build-up of some sort of tolerance to seeing this, and I guess the unfortunate side of that is that a serious patient may be missed," Mr Murray says.
But while the focus for ambulance crews is users, police have a different target.
"There's no power for arrest for the possession of synthetics but in terms of the suppliers there is a power for arrest and that's where we are concentrating on," says Auckland City Police detective inspector Scott Beard.
Figures released under the Official Information Act reveal the number of alleged synthetic drug offenders has more than doubled from 252 in 2014 to 511 last year.
Most offending took place in Auckland, Bay of Plenty and Canterbury, mainly relating to the possession, sale and supply of the drug.
In one case an offender was as young as 10 years old.
"A lot of times our staff just come across people in the street who have a lot of synthetic drugs on their person," Det Insp Beard says.
Other times larger operations are discovered during search warrants. In Tauranga earlier this month police seized more than 8 kilograms of synthetics in one operation.
Police say the drug is cheap, strong and targets vulnerable members of society like the homeless.
"In the winter it's cold they're out on the street, they feel warm and also the unconsciousness, it passes the time for them," says Insp Beard.
The penalty associated with synthetics is two years in prison. But police say submissions will be heard to push for a law change which could include a higher penalty.
Newshub.
