Rural Women New Zealand is accusing ACC of jeopardising the healthcare of up to 600 rural beneficiaries by slashing the travel expenses their carers receive.
From Tuesday, the Accident Compensation Corporation will no longer reimburse health workers for the first 20km they travel to visit their patients.
ACC says it will pay for any mileage past 20km per day, at a rate of 62 cents per kilometre.
Rural Women's executive officer Noeline Holt says most home care companies run on a 3% profit margin and cannot make up for the reduced travel allowance.
Ms Holt fears some contractors will be forced to withdraw services and some may be bankrupted.
ACC says it is surprised by the claims, saying it believes its rural beneficiaries could be among those least disadvantaged.
The corporation says it is relatively confident that its new rates are reasonable, based on consultations with care agencies.