Three people have been taken to hospital after it's believed they ingested a substance outside Auckland's SkyCity.
Emergency services rushed to Federal St just after 8:30am. A rapid response team and an operations manager were also sent to the scene, a St John spokesperson said.
Three people were taken to Auckland City Hospital in a critical condition.
"Initial indications suggest that the three people have suffered a medical event after taking an unknown substance," a police spokesperson said.
"They have been transported to hospital for treatment."
A witness told the NZ Herald he believed the trio had consumed synthetics.
"They just passed out. It wasn't good."
Police said an investigation is underway.