The Cancer Control Trust, which advocates for better cancer care, is protesting against the health minister's decision to disband a ministerial advisory committee.
The committee, Cancer Control New Zealand, was set up in 2001 to improve treatment, including waiting times for diagnoses and therapies.
The minister, Jonathan Coleman, said it was no longer needed thanks to progress made in improving cancer services.
But chairman of the trust, Brian Cox, said an Audit Office report on the Faster Cancer Treatment Indicators championed by the minister found the indicators to be unreliable.
Mr Cox said cancer death rates were higher in this country than in Australia and independent advice from a single agency was the best way to improve survival rates and monitor how effectively money was spent on care.