A woman visiting her partner in prison was trapped inside for more than three hours despite screaming out for guards and throwing a chair at a window to get their attention.
Prison managers say the incident was regrettable and happened because Corrections officers did not follow procedure.
On Tuesday Lorraine Haare drove from Opotiki to Rimutaka Prison in Upper Hutt to see her partner who is 9 months into a three-year sentence for a drug conviction.
She arrived at 2.45pm and was escorted to a visiting room, where she was to have two hours with her partner.
But when their time together was up, no one showed up to let her out.
"We screamed for a good hour, then had a break, then screamed for another hour - we didn't know what to do," she told the Weekend Herald.
"So I picked up a plastic chair and threw it at one of the small viewing windows to try to get out."
The window broke but no alarm went off. Ms Haare then climbed through the window into an adjoining office.
There was no phone in the office so she couldn't call anyone for help.
She ran back to her partner who told her to try yelling one more time and then if that didn't work, set off the fire alarm. "We were completely forgotten about," she said.
The guards eventually heard her yelling - three hours after she was supposed to have left the prison - and let her out.
"And finally these guards heard me and they came down but they thought it was a joke."
The Department of Corrections apologised to Ms Haare, but she is demanding the prison review its practices so the same thing doesn't happen again.
"But I don't think that's good enough - what if something had happened to us? We were completely forgotten about," she said.
"And what about my partner? They didn't even realise he was missing. Dinner was at 4.30pm and he wasn't there - didn't they notice?"
Rimutaka Prison manager Richard Symonds said Ms Haare and her partner were left to spend time together in a "non-contact visits booth".
"In the booth the prisoner and visitor are separated by toughened glass. When the visitor arrived she was processed according to procedure," he said yesterday.
"Unfortunately policy was not correctly followed when logging visitors out of the prison which resulted in this visitor, and the prisoner she was visiting, being left in the booth for an extended period of time after the visit was scheduled to finish. We deeply regret the distress caused to this visitor. She had been assigned a non-contact booth as per proper procedure, and as she had travelled a considerable distance her visit had been approved to last an extra half an hour."
Mr Symonds said Corrections had robust policies around visits.
"And this goes completely against our policies. These policies were reinforced as recently as January this year and promulgated to staff. An investigation into this incident began immediately. I have personally been in contact with the visitor and the prisoner to apologise.
"At no point was the visitor at risk of physical harm."