Illegible handwriting is being blamed for nearly 7,000 identity documents found to have incorrect information every year.
Figures released under the Official Information Act show 17,852 births, deaths and marriage certificates, more than 1,000 passports and hundreds of citizenship certificates were found to have incorrect details over a three-year period.
Department of Internal Affairs spokeswoman Jo Watt said the flaws were mainly caused by poor writing. "For the most part the departmental errors result from misspellings of names and other information, particularly where the department is interpreting handwritten applications."
Out of the flawed certificates, 1,326 incorrect ones were sent out before Internal Affairs staff picked up the mistakes. Among passport errors, common mistakes were passports being issued in the incorrect sex (187), the wrong name (141), and the wrong image being used (85).