The Cancer Society is worried that the National Bowel Cancer Screening programme may be under-funded.
Health Minister David Clark revealed yesterday that 2500 people had not received invitations to be screened for bowel cancer under a pilot programme because their addresses were not updated.
The Health Ministry said some people moved and with no forwarding address available, the invitations failed to reach them.
Three of those not offered screening went on to develop bowel cancer, and one died.
National Screening Unit clinical director Jane O'Hallahan said they identified the problem last September and had fixed it, but were very sad for what had happened.
"Our job is to make sure that we find these issues with screening and that we address them carefully and properly and provide them with the most high quality screening programmes that we can," she said.
Dr O'Hallahan said the screening register had been updated by cross-referencing people against their National Health Index number.
Mr Clark said the problem would be part of a future broad review of the national screening programme.
But Cancer Society medical director Chris Jackson said he was concerned about a lack of funding for the programme.
"The bowel cancer screening programme appears to have been underfunded for some time.
"Initial estimates were that the programme were going to cost more than $60 million a year and it's clear that that amount has not been allocated to the forward funding of the programme," he said.