The woman was on the property for a very brief period before she was seen by a police officer stationed at the facility.
Police said the 45-year-old had no contact with anyone at the facility and has been charged with unlawfully being on a property.
It is the first time anyone has been charged with sneaking into a facility.
Previous incidents have been of people leaving or attempting to escape various managed isolation facilities in Auckland and Hamilton, though not all have been charged.
The latest, on Tuesday, was when a man attempted to walk out the front door of a facility and a security guard intervened.
The person was handcuffed and taken back to his room where he received a verbal warning from police, Air Commodore Darryn Webb said.
In giving a suspended sentence to a woman for fleeing isolation in Auckland, a District Court judge this week described the lack of mental health assessment and additional care for those suffering from such issues in managed isolation as "a major failing".
Attempted escapes from isolation facilities:
July 4 - Suzanne Derrett (43) fled the Pullman Hotel in Auckland by climbing a fence. She was given a six-month suspended sentenced in Dunedin District Court on August 4.
July 7 - A 32-year-old man slipped through a fence at Auckland's Stamford Plaza and supermarket walked to a nearby supermarket. He later tested positive for Covid-19. He was expected to be charged and face the court process once released from quarantine.
July 9 - Martin McVicar (52) was accused of breaking through a fence at the Distinction Hotel in Te Rapa, Hamilton to visit a nearby liquor store. He was charged and remanded in custody.
July 10 - A person in their 60s broke a window and scaled a fence to escape from the Waipuna Hotel in Mt Wellington, Auckland.
July 24 - A 37-year-old woman and her four children, who were in New Zealand for a funeral, left the Distinction Hotel in Te Rapa to visit the body of the children's father. Four members of the family pleaded guilty to charges. The youngest child, 12, was not charged.
July 30 - A 32-year-old man is accused of following a staff member out of the Crowne Plaza Hotel in Auckland. He didn't make it more than 100m down the road. He has been charged.
August 4 - Man tried to walk out of an unidentified facility. He was handcuffed, and returned to his room and given a warning, Air Commodore Air Commodore Darryn Webb said.
