Some of the 10,000 people unknowingly withdrawn from a bowel screening list may have been waiting for up to five years, the Ministry of Health says.
The 10,349 people, aged between 60 and 74, were cut from the Waitemata bowel screening pilot programme because their addresses on the National Health Index were not current, NZME reports.
Information released to NZME under the Official Information Act shows the people were put back on the recall list after the error was discovered in September last year. Officials are unsure how long they had been excluded from the list.
For three people who were found to have cancer after not being invited to join the programme, a clinical review concluded an earlier diagnosis could have been in their best interests. It could not be determined whether this would have helped their diagnoses.
Five other people were also found to have cancer after not being invited to join, two of whom have died, NZME reports. It has been concluded an earlier diagnosis would have not altered their prognoses.
After realising the mistake, the Waitemata District Health Board checked names from returned mail against their patient system. It also asked those eligible who had not been invited to get in touch.
The full programme is being unrolled across the country over the next few years. The Waitemata DHB website describes the programme as a test which can "help find cancer early when it can often be successfully treated".
"Every two years you will be sent an invitation letter, a consent form and a free bowel screening test kit. The test is done at home, and is clean and simple to do."