A Taupo woman who had a breast removed even though she didn't have cancer is confident other women won't go through the same ordeal if promised changes are implemented.
In a report released on Thursday, the Ministry of Health said that in the past two years, mistakes at laboratories resulted in five patients receiving major surgery they did not need.
The ministry convened a panel to study how samples of breast and oral tissue from nine patients were mixed up or wrongly diagnosed at hospital and community laboratories.
It meant that three women had breasts removed unnecessarily, one had breast surgery for a tumour that wasn't there, and one had part of her top jaw cut away for no reason.
Taupo woman Jenny Engels had a mammogram which found inconsistencies and had surgery to remove her left breast after tests came back positive.
She told Radio New Zealand's Nine to Noon programme it was not until some time later that she was told the positive results related to someone else.
The different labs that made the mistakes in five cases have already reviewed and improved how they do things, and all the rest are being given until November to do the same.
Ms Engels says if those changes are followed, then the report has been worthwhile. "If they are all put into place and followed to the letter so this doesn't happen to anybody else then that'll have been a worthwhile report."
Breast Cancer Aotearoa Coalition chair Libby Burgess says despite these errors, breast screening is important and needs to continue.
"It is the system in place that protects New Zealand women and ensures fewer of us will die of breast cancer."
Ms Burgess says 71% of women aged between 45 and 69 have mammograms.
Women apply for ACC
Three of the women who had unnecessary surgery have applied to the Accident Compensation Corporation for lump-sum compensation for treatment and injury.
ACC chief executive Ralph Stewart, says the corporation recognises the women have endured a traumatic experience and acknowledges the challenges they're now facing.
Mr Stewart says ACC is respectful of the women's individual concerns and will do all it can to ensure they receive the benefits they are entitled to under legislation, and will be supported through the process.