More than 1800 Wanganui criminals have been allowed to hide convictions like aggravated assault and bestiality from prospective employers under a law that came in a decade ago.
The Clean Slate Act allows people with less serious convictions to have them concealed if they have been conviction-free for seven years and meet other criteria.
More than 1800 Wanganui criminals have had their record cleaned since the act came into force in November 2004.
In that time, the Clean Slate Act has concealed 7450 local convictions from prospective employers, including aggravated assault with a weapon, bestiality, fraud and careless driving causing death.
One Wanganui criminal had amassed 55 convictions, but was able to hide them from employers under the clean slate law.
To be eligible for a clean slate, someone must have been conviction free for the previous seven years, never received a custodial sentence, and not be convicted of a "specified offence".
Specified crimes including sexual offending against children and the mentally impaired can never be concealed.
Whanganui Employers' Chamber of Commerce president Craig Hanford said although he was confident the clean slate criteria were "reasonably stringent", it highlighted the problem of local employers failing to do due diligence on potential employees.
"Some [employers] are excellent, but I know a number who don't ring referees or do background checks on job applicants."
The onus was on employers, particularly when employing someone in a position of trust, to do background screening.
Not doing your research could be "catastrophic", he said.
"Trust your instincts, if something feels wrong with a new or existing employee, don't be afraid to dig a little deeper."
Nationally, 115,079 people have had their slates cleaned since November 2004.
One Auckland criminal had the luxury of concealing their former crimes, despite having racked up a staggering 232 convictions - the country's worst.
Business New Zealand chief executive Phil O'Reilly said employers should always be able to see an applicant's history.
"If you've had a dishonesty offence and a small retailer is going to employ you behind the cash till, that's directly relevant, whether it's one [offence] or 232," he said.
However, Pathways Trust reintegration manager Carey Ewing said the clean slate law allowed former criminals to put their mistakes behind them.
"New Zealand can be a particularly unforgiving environment [and] I don't think any of us would like to live a life where we were solely judged upon the mistakes we made in the past."
Exaggerated media coverage of criminal offending had helped fuel Kiwis' beliefs that people didn't change and the longer offenders went to prison, the better.
A clean slate gave someone opportunities that public opinion would not, he said.
The clean slate process is automatic, but only applied when a criminal history request is made to the Criminal Records Unit - which processes about 450,000 requests a year.
Although clean slate histories are hidden from most employers, convictions are still disclosed in applications for jobs as police, judges, and roles involving the care of children.
Criminal histories are also visible to law enforcement agencies.
Convictions are also visible to overseas immigration authorities.