The clean slate law was primarily designed for those who have committed lesser crimes but a High Court judge has concealed the history of a paedophile in a landmark court case.

A former teacher convicted of repeated sexual offending against an 11-year-old boy has been granted a clean slate so he can work in aged care, despite objections by those in the industry and another judge.

It is the first case of its kind to reach New Zealand's High Court, with those convicted of sexual offences ordinarily exempt from the law designed for people who have committed lesser crimes.