The Health and Disability Commissioner has recommended the Nursing Council reviews whether a nurse is fit to work after she injected a woman with a used syringe and then went on leave without telling her.
In June 2013, the unnamed nurse, who works at a doctor's surgery, gave a woman an injection then put the syringe back in its box and used it on her next patient.
The nurse realised her mistake immediately and told the patient the syringe was empty but didn't tell her she had injected her with a used needle.
She told her employer but failed to contact the patient, as she went on leave for four days.
The nurse also neglected to weigh the woman and check her blood pressure before giving the injection but wrote in the patient's notes that she had.
When the nurse returned to work, blood tests were done to ensure the patient hadn't contracted anything from the needles and the results were negative.
The commissioner said the nurse showed a lack of reasonable care and skill.