A woman working for Child, Youth and Family (CYF) started a sexual relationship with a boy in the teen unit where she worked.
The Herald on Sunday can reveal the woman, who worked at Te Maioha o Parekarangi in Rotorua, was moved to another unit after the relationship was uncovered. She has since left.
Authorities called in police but because the boy was 17 at the time, no laws were broken.
A police spokeswoman confirmed officers had investigated: "No criminal offence was identified and there is no further police action," she said. It is unclear whether the woman was stood down after CYF's investigation.
Nova Salomen, general manager residential and high needs services for CYF, said the inappropriate relationship came to light last year.