Many claimants had begun to feel they were part of an "underclass", which was not receiving the same privacy rights as their fellow citizens.
"We've been dehumanised and reduced to a client number," she said.
Two recent independent reports into the ACC privacy breach, which found "systematic failure" in ACC's privacy protection, were likely to have far-reaching implications, Dr Powell said.
They highlighted, above all, that claimants still had a right to reasonable privacy.
The president of Acclaim Otago, a claimant support group, she earlier made submissions in person to a recent review of ACC's privacy practices initiated by Privacy Commissioner Marie Shroff.
Dr Powell's name and those of about 470 Otago ACC claimants were on a list of 6725 people mistakenly emailed to Auckland resident Bronwyn Pullar in a major privacy breach late last year.
Concerns have also arisen recently involving Inland Revenue, which has had 32 privacy breaches involving 6300 people in the past year.
In its report, an independent review team commissioned by the Privacy Commissioner took issue with several aspects of the ACC 167 consent form, noting its broad nature.
There was "an opportunity for a better practice review" and the team "strongly" encouraged ACC to consider "detailed consultation" with those affected in any review.
Asked if work had begun on the consent form, ACC lead media adviser Stephanie Melville said ACC had "commissioned a three-year work programme to implement all the recommendations" identified in the inquiry report, released in August.
"Good early progress is being made. However, it will take time to complete them all as the recommendations include changes to governance, strategy, systems and culture," she said.
Dr Powell said ACC was entitled to ask claimants for relevant medical information to assess claims, but claimants also had the right to know what information was being sought about them and why it was needed.
Complying with the Privacy Act would result in more humane dealings with ACC clients, she said.
