Employers, recruitment agencies given access to claimants' histories 36,000 times in the past year.
ACC gives details of tens of thousands of people's injury claims every year to recruitment agencies and prospective employers.
In the past year, 36,000 of these requests were processed, the Accident Compensation Corporation said.
Employers use the information to help decide whether to hire a job applicant, but even asking a jobseeker for consent to obtain their ACC records can be unlawful under the Human Rights Act.
The extent of the ACC's assistance in job recruitment has emerged after a judge found ACC acted unlawfully in suspending the entitlements of claimants who refused to sign a wide-ranging privacy waiver.
ACC is reviewing the privacy waivers it asks all claimants - it handles 1.7 million claims a year - to sign.
Council of Trade Unions president Helen Kelly said it was now a widespread practice for employers to seek access not only to a jobseeker's ACC records, but also to bank, credit and medical information.
ACC will release a claimant's information to prospective employers and recruiters only with the person's permission.
But the Human Rights Commission says employers should generally not ask jobseekers for authority to see their ACC claims history. Nor should they ask about any health or disability matter, because it is unlawful to discriminate on grounds of disability - unless it is directly relevant to the applicant's ability to do the job.
Horizon Recruitment's website lists the company's pre-employment screening and checking services as including "accident compensation history - manage your business risk if the candidate is prone to injury".
"By verifying a candidate's accident compensation history, you will be able to assess persistent claimants, assess if a candidate is appropriate for the role ..."
Owner John Henderson said, "If we have the [job applicant's] authority to it, it's fine."
ACC Minister Judith Collins said she was not aware of the extent of the requests for information from ACC.
"I will find out why that would have happened and once I've got the information then I will make a judgment call."
• ACC will release a claimant's information to prospective employers and recruiters only with authorisation - in line with the Health Information Privacy Code.
• It withholds information on mental injury as a consequence of physical injury, declined claims, treatment injury claims, claims occurring more than 10 years ago, sensitive claims, or self-harm claims - unless the claimant gives specific consent for its release.