A Christchurch man has been convicted for sexually grooming an underage boy on gay dating app Grindr.

The 53-year-old was sentenced to three months' community detention and 150 hours of community work at Christchurch District Court yesterday.

The 15-year-old had initiated a lot of the communications between the pair and did not want the man charged, the court heard.

Judge Kevin Phillips sentenced the man to three months' community detention and 150 hours of community work.

He is subject to a 8pm to 5am curfew, nine months' supervision, and must not have contact with people under the age of 16 without supervision. He was not placed on the Child Sex Offenders' register.