Gately was last known to be in Kaikoura.
Detective Sergeant Chris Power said Gately, who has convictions for rape, assault with intent to commit rape and abduction for sex, was regarded as a "high risk offender".
Gately was serving a sentence of preventive detention for serious sexual offending committed in 2000.
According to a parole board decision earlier this year, one of the offences was committed within three months of his release after serving the mandatory two thirds of a sentence of his eight years imposed for rape in 1994.
After graduation from the Adult Sex Offender Treatment Programme and obtaining release to work, Gately was released in May last year, with standard conditions imposed.