ACC boss Scott Pickering says it will be a couple of years before work to better harness its "mountain of information" kicks off.

ACC is moving in the right direction by pushing ahead with a $456 million overhaul, people dealing with the state-owned insurer say.

Spinal Trust chief executive Ben Lucas, who chairs ACC's serious injury advisory group, said there was always going to be apprehension about changes.

These include a push by ACC to make more use of data and analytics when determining "treatment pathways".

But Lucas said the state-owned insurer had been adopting a culture of putting "people before process".

READ MORE: ACC gets approval to push ahead with 'low-margin' $456m overhaul

Auckland lawyer Hamish Peart, who advocates for claimants, said ACC's existing systems were cumbersome and he was hesitantly optimistic it was heading in the right direction.

Despite the planned investment in data analytics, there had been no suggestion ACC was going to assess claims in a more mechanical fashion, he said.

Better systems were needed to remove frustrations for clients and it appeared ACC was adopting a more "customer-centric approach", he said.

"One of the big problems our clients have is they have to deal with different managers in different 'silos' of ACC if they have more than one claim or more than one type of entitlement.

"It is a little bit of a mess. In fairness to ACC there are a huge number of claims and documents they have to manage."

Government advisors have cautioned the "Shaping our Future" technology and business overhaul may not pay for itself if cost overruns eat up the cash that has been set aside for "contingencies".

But ACC chief executive Scott Pickering, who was appointed in 2013, said the project would only lead to an increase in levies "in the worst case scenario" which he intended to avoid.

ACC didn't expect cuts to its workforce of 3300 but would have had to increase staffing levels if it was not making the investment, he said.

It would only use improved software systems to guide decisions on "treatment pathways", rather than to automate them, he said.

"We sit on a rich mountain of data – we have got 42 years of information in our system – and it is about using that in a more effective fashion."

Peart did not believe ACC advocates would be put out of business by Shaping our Future, saying those who remained in the field were busy.

"There used to be hundreds of personal injury lawyers and now there are just a handful of us who are specialists. What we'd prefer to be doing is arguing those complex and tricky cases that are at the margins."

While ACC had been taking a more conciliatory approach to disputes, that could ebb and flow, he said.

"There has definitely been a movement towards more dispute resolution, as opposed to fighting everything, but we are still getting a large number of inquiries on a regular basis.

"We see fluctuations in the long and short term trends and they are often driven by political and financial circumstances, if you are being honest. At the moment, ACC has been making a concerted effort to behave better and regain trust and confidence," he said.