A teenage boy has died after ingesting an unknown substance with six other teens in north Queensland.

Emergency services were called to a home in North Mackay just before 11am on Thursday.

Police say the boy suffered a cardiac arrest and emergency paramedics transferred him to the Mackay Base Hospital before he died early on Friday.

Six teenagers – three boys and three girls – aged between 12 and 17 were also taken to hospital after being suspected of ingesting the substance.

Police said a crime scene had been declared at the Malcomson Street residence, while a 36-year-old woman who is a parent of one of the children was being questioned.

“We do not currently know what the children ingested. We will have to wait for results of blood tests and toxicology in order to confirm what the substances were,” Detective Inspector Tom Armitt said.

“This matter is now subject to a coroner’s investigation, and as such, police will be conducting a number of inquiries and interviewing those people present at the address, including the affected children, in order to determine the facts and the circumstances leading up to the calling of emergency services.”

Police say they are uncertain where the children were when the substances were ingested.

-AAP