About 200 sexual abuse victims caught up in the ACC privacy breach have been offered an "insulting" $250 in compensation and are mulling fighting the corporation for more money.

Lawyer John Miller says he believes their case is strong and his firm will take action on a pro bono basis on behalf of about 100 of his sensitive-claim clients, Radio New Zealand reports.

He told the broadcaster he would go to the Human Rights Tribunal if negotiations failed with ACC and the Privacy Commissioner, following the "insulting" $250 offer in June.

ACC has paid out more than $185,000 in compensation for 32 privacy breaches in the last seven-and-a-half years - an average of nearly $6000 for each of them.

However, another lawyer, Hazel Armstrong, warns the sexual abuse victims may have to pay anything between $2000 and $7000 for a psychiatrist to prove they've suffered emotional harm because of the privacy breach.

ACC chief executive Ralph Stewart said the $250 was chosen because of the numbers involved and an acknowledgement of ACC's error.

If claimants were not happy with that they were welcome to discuss it further with ACC, he said.

In August last year, ACC mistakenly sent the details of about 6500 claimants to former National Party insider Bronwyn Pullar.

It was one of New Zealand's biggest privacy breaches.

The Privacy Commissioner's investigation found systemic weaknesses in the corporation's culture, systems and processes, which left it open to potential breaches of privacy.