The man jailed for killing four-year-old James Whakaruru was released from prison on Monday morning.
The Hawke's Bay boy died from extensive internal injuries in 1999 after prolonged beatings from his mother's partner, Benny Haerewa.
The Parole Board says it has grave fears about the high risk Haerewa poses to the community as a serious violent offender.
But he must now be freed by law, having served his full sentence for the boy's manslaughter.
The Probation Service is monitoring Haerewa for the next six months and, for a start, he will be visited every day.
The service's general manager, Katrina Casey, says this is to assess his risk profile and ensure his release conditions are adhered to. He will be recalled to prison if they are not.
Ms Casey says Haerewa is cooperating for now and does have some family support, "but he is a high-risk offender and he can change his attitude and his behaviour at any time".
At the moment, she says, "He's probably best described as a bit overwhelmed."
Haerewa has agreed to an overnight curfew, which will be electronically monitored until his conditions expire in June.
The service refuses to specify where he has been released to, saying it could prejudice his successful reintegration into the community.