Ms Patel worked the night shift, between 3.30pm and midnight, six days a week. During that time, one cleaner was meant to be assigned to an operating theatre for the entirety of the shift.
However, the court was told that in January last year, she assigned one cleaner to an operating theatre, as well as radiology.
The operating theatre failed a quality assessment audit the next day.
At a disciplinary meeting, Ms Patel claimed she was stretched in terms of staff resources, and took on cleaning duties herself that night.
However, the company had previously made it clear that critical areas were to be given priority over non-critical areas, and that one staff member was needed to clean a theatre.
In her decision, Judge Christina Inglis said Ms Patel had been reluctant to accept there had been issues that were the subject of ongoing discussions with the company.
In a statement, Auckland DHB said it had taken control of cleaning. "To ensure high standards are met and maintained, as of last week our cleaning staff transferred to direct employment."