ACC received 5055 new sensitive claims last year, and is expecting a 10 per cent increase in claims each year until 2020.
ACC strategy manager for sexual violence Emma Powell said the overhaul would give victims more time, funding and choice.
"We are no longer going to be approving 10 counselling sessions here, or 10 there, we are actually saying 'Here's 12 months, you and your therapists ... build a programme around the person's needs ... and that's about providing a much more holistic approach'.
"We're throwing away the calendar and throwing away the clock and just letting people focus on getting better."
The cost of the upgrade cannot yet be revealed, but it was expected to require a doubling of funding. ACC spent around $45 million on sensitive claims in 2012/13.
At present, ACC funded counselling for rape victims but only up to $80 for a one-hour session. Counsellors often charged a "top-up", or additional fee of up to $90.
Ms Powell said the corporation was concerned that this cost was putting people off a crucial service. Claimants were taking an average of 7.8 sessions despite being entitled to 16 sessions, or more depending on their circumstances.
Under the new service, ACC would cover the full cost of the sessions. The overhaul would also allow victims to shop around for a therapist who they felt comfortable with.
Therapists, psychologists or psychotherapists would be given travel funding to allow them to reach people in isolated regions.
ACC and its partner agencies planned to increasingly include family members or support people during the recovery process, though it was not yet planning to extend its services to perpetrators.
At present, adult sexual abusers can get funded treatment only if they are in the criminal justice system. This meant there was a gap in the system because many victims knew their abusers and did not want to place charges, but wanted them to get treatment.
This problem was raised at a wide-ranging Parliamentary inquiry into specialist sexual violence services. The inquiry has been told of long waits for specialist services, uncertainty about continued funding, and the struggle to help Maori, rural, transgender or intersex clients.
Funding changes
*All counselling sessions for sensitive claims will be fully funded.
*Claimants can get access to 48 therapy sessions over 12 months, as well as other treatment.
*Victims can shop around for a counsellor they can trust.
*Family members or support people will be included in treatment where appropriate.
*Therapists will be funded for travel to allow them to visit isolated regions.