Prof Cox, a University of Otago public health specialist and epidemiologist who was involved with the development and monitoring of the country's breast and cervical screening programmes, said he was surprised by the planning of, and approach to, the pilot, which involved a "certain amount of naivety".
He was not sure a pilot which would be limited to 130,000 people in the Waitemata District Health Board area would provide "answers relevant to the whole of New Zealand".
Health Minister Tony Ryall announced yesterday the Waitemata District Health Board had been selected to run the $24 million four-year pilot, which will begin in October next year.
Prof Cox, speaking from Australia, said he remained concerned the screening pilot was using only faecal occult blood testing (FOBT), when recent studies had shown the benefits of offering a one-off flexible sigmoidoscopy (a procedure which internally examines much of the bowel).
Planning for flexible sigmoidoscopy would have to involve nurses and general practitioners being trained to do the procedure, and how well that would be accepted would depend on the attitude of gastroenterologists and the medical council, he said.
Beat Bowel Cancer Aotearoa chairwoman Dr Sarah Derrett, of Dunedin, said the delay was "heart-breaking" and the pilot appeared to be "nothing more than a stalling tactic designed to save money".
It appeared it would be at least 2016 before the information would be in from the pilot and it could be a long time after that before a decision was made on whether to proceed further.
Dr Derrett said the organisation appreciated screening programmes were complex and needed to be introduced carefully, but it considered there was adequate information on the success of screening from other countries.
"The Government's long and drawn-out proposed pilot will simply delay effective action to save lives."
Colorectal cancer was the second-biggest cancer killer in New Zealand, after lung cancer.
By the time the pilot started, there would have been another 1250 deaths.
Only about 60% of bowel cancers were cured. Early detection of the disease was the key to improving such statistics.
She agreed there was a risk FOBT screening would have been superceded by the time the pilot was completed and there was a risk that could result in further delays.
Dr Derrett said she was also a "little surprised" the Ministry of Health did not consider the possibility of also including flexible sigmoidoscopy in a trial.
Concern was also expressed by the charity about the inequity of access to colonoscopies around the country.
