A warrant to arrest has been issued for a Christchurch man who entered into an incestuous relationship with his sister.

The siblings, both of whom have automatic name suppression, met as young adults and now co-parent a young child together.

The sister was last month sentenced to three months community detention on the incest charges.

The man was due for sentencing this afternoon but failed to show.

He was also due for sentencing on a charge of wilful damage and a breach of a community work sentence.