Up to 10 adolescent boys have suffered bleeding and infections from circumcisions that have gone wrong.

A spokeswoman for Middlemore Hospital in south Auckland says they've been sent to Starship children's hospital for treatment.

The most recent case was on Monday.

An NZME source understands the surgeries were performed without anaesthetic in Otara.

It's unclear whether the man said to have performed the operations was a registered medical practitioner, and it's believed he has left the country.

A complaint has been made to the Ministry of Health.