The Accident Compensation Corporation rejects claims it is denying funding for rehabilitating people with serious brain injury in an attempt to cut costs.
The Brain Injury Association says it has evidence this happened to 12 people whose claims have been rejected this year.
Association president John Clough told Nine to Noon he started collecting evidence after concerns that some people's claims recommended by doctors, were being rejected.
Mr Clough says 25 rehabilitation providers for the brain injured have closed in the past few months and large private rehab services are also reporting a marked drop in the number of referrals from ACC.
ACC says the association's claims are not reflected in the figures it has.
ACC national serious injury service manager Liz Cairns says the number of brain injury claims has not decreased and ACC has been spending more in the past three years, rather than less.
Ms Cairns told Nine to Noon she would welcome the opportunity to discuss the 12 cases the Brain Injury Association has and investigate why the claims were rejected.
