Dunedin Hospital has apologised to nearly 4000 patients after losing their breast scan images.
The Southern District Health Board appeared before the Parliamentary Select Committee today over budget issues and admitted the error.
They say mammograms taken between February 1 and October 31 2012 were lost due to a computer glitch.
"I would like to apologise to the 3,850 people who received a mammogram in Southland during this time and whose images have been lost," says Southern DHB Chief Executive Officer Carole Heatly.
Ms Heatly says letters are going out to all patients who've had scans at the hospital and their GPs.
She says the images had already been reviewed by doctors before they were lost and no-one's safety is at risk.
"We want to reassure all patients that there is no change in the outcome from those mammography images," says Ms Heatly.