Health and Disability Commissioner Ron Paterson says a morbidly obese woman was insulted and demeaned by a surgeon who used foul language when she consulted him last year about gastric bypass surgery.
She was also removed the woman from the waiting list after she complained.
Mr Paterson says the surgeon used the f-word when the woman said she wanted to take a holistic approach after the surgery, rather than focusing on diet.
He says the surgeon showed disrespect for the patient and removing her from the waiting list appeared to be in retribution for her complaint.
Mr Paterson says the surgeon should attend a course in communication skills and his employer at a district health board should have done more about his behaviour.
Associate Health Minister Tariana Turia says the surgeon abused his role and power by using such language and showed no respect at all.
Mrs Turia, who is the woman's MP, says the DHB should now arrange for the operation to be done elsewhere and pay the bill.
Radio New Zealand's health correspondent says the 44-yar-old woman was morbidly obese, with a body mass index (BMI) of 68.
According to the Health Ministry website, a BMI over 32 is considered obese for Maori adults.