Pacific Radiology, which supplies the breast cancer scanning service for the Ministry of Health, has contacted 43 women whose scans might be at issue.
A further 16 women who were referred to Pacific Radiology by the Southern District Health Board or through a private physician have also been contacted and asked to return for further assessment.
Pacific Radiology clinician Jacqueline Copland said questions had arisen over the work of a former employee, which had led to 5461 screening mammograms performed by that person between May 2020 and 2021 being reviewed.
The National Screening Unit within the Ministry of Health was aware of the issue, Dr Copland said.
All of the scans would have been double-checked but Pacific Radiology had chosen to review the 60 selected scans to ensure the safety of the women concerned, she said.
The problem had been detected during routine quality control checks.
"Recalling a woman for assessment does not mean that woman has breast cancer, and most women who are asked to come back in for assessment do not have breast cancer," Dr Copland said.
"At the assessment clinic, each woman will have further tests to clarify the appearances from the screening mammogram, and some women may require a biopsy."
SDHB chief medical officer Nigel Millar said Pacific Radiology had informed it of the issue.
"We appreciate the conservative approach they are taking in reviewing all imaging, and recalling women where there are questions," Dr Millar said.
"We will continue to work with Pacific Radiology to ensure women receive the care they need."
Dr Copland said Pacific Radiology understood that the recall might cause distress for those involved, and apologised to all women who had been affected .
"Our primary concern is the safety of all women, which is why the decision was made to review all the breast imaging performed by this doctor."
