The Christchurch mother of a baby who chewed on a bag of methamphetamine has been sentenced to supervision

The 11-month old boy was only taken to hospital after an intercepted phone call the mother made to an "associate" in prison alerted authorities.

The baby didn't suffer any ongoing or adverse medical issues.

The 30-year-old pleaded guilty to causing a criminal nuisance.

The judge sentenced her to 18 months of intensive supervision, plus 12 months' judicial monitoring to keep him up to date with her progress.