The New Zealand Medical Association (NZMA) says it has "serious misgivings" about a new at-home bowel screening programme.
Beat Bowel Cancer Aotearoa today launched its faecal occult blood test kits, which are available from pharmacies for $59.99.
The kit includes brushes and test cards so people can collect a faecal sample and send it to a lab in Sydney for testing.
Results are sent to the individual and their doctor.
NZMA chairman Peter Foley said he was concerned the programme was set up without consultation with the medical profession.
"GPs are better placed to provide this service as they are aware of a patient's history, which is a very important part of screening," he said.
"Point of care testing is desirable in the right settings but it must be linked with the rest of the enrolled patient's care. The test itself is only part of screening. The patient's history and an understanding of false negative and false positive results need to be managed."
Dr Foley said he the kits could also falsely reassure people or cause them to worry unnecessarily.