Department of Correctional Services staff allegedly found a resealable bag containing green plant matter, which police believed to be cannabis, during a routine vehicle search as the 22-year-old was entering the Cessnock Correctional Centre grounds on Sunday morning.

Central Hunter crime manager Detective Inspector George Radmore said the woman became “irate” when police were called to the scene and began screaming at officers and threatening self-harm.

Inspector Radmore said the woman then ran from police into the jail grounds before she fell and was detained.

An ambulance was called to the scene and paramedics took her away for mental health assessment.

Inspector Radmore said police expected to charge her with possessing a prohibited drug and attempting to take a prohibited drug into a jail.