To ensure their invitation reached them, people should check their GP/community health practice had their current address.
Screening will be offered to those eligible for publicly funded health care and aged 60 to 74, unlike the pilot programme, which begins at 50.
BCNZ executive member Professor Sarah Derrett said: "We know that 11% of those diagnosed with bowel cancer are in the 50-59 year age group.''
These people were denied access to the screening programme but the organisation felt if they had blood detected through a faecal immunochemical test kit from a pharmacy, they ought to be considered for further investigation no matter where they lived. (Pharmacy FIT kits have a higher threshold for detecting trace blood in faeces than the test used in the national screening programme.)
"This is especially crucial for the majority of DHBs who do not yet have a screening programme in place.''
Earlier this year, The Star reported the case of symptom-free 65-year-old Brighton man Michael Horgan, who did not qualify for a public colonoscopy after a positive pharmacy FIT kit result. His cancer was diagnosed following a private colonoscopy.
Prof Derrett said two groups adversely affected by the national screening programme starting at 60 were Maori and Pacific New Zealanders.
For these groups, more than 22% of bowel cancer diagnoses occurred in the 50-59 year age group, he said.
District health boards were required to reduce health disparities for these groups and, by not accepting referrals by GPs following positive pharmacy FIT tests for Maori and Pacific people, they might increase inequities.
In response to questions related to the pharmacy kits, the Ministry of Health's director of service commissioning, Jill Lane, said a positive occult blood test did not move an asymptomatic person to be considered symptomatic and potentially eligible for publicly funded colonoscopy.
Evidence of symptoms was assessed by a family doctor based on any abdominal pain, change in bowel habits or visible blood in faeces, not the microscopic level of blood detected by the FIT kit.
There was a range of reasons why microscopic traces of blood might be present in faeces.
It was important to note only 7% of those with a positive FIT referred for colonoscopy were expected to have a cancer diagnosed, she said.
