An osteopath will face a disciplinary tribunal after allegedly massaging a woman's breast to treat a toothache.

The Christchurch practitioner could have his registration cancelled after the Osteopathic Council of New Zealand professional conduct committee found it had grounds to lay charges.

A five-month investigation started when the woman complained to the council, Health and Disability Commissioner and police after the consultation on October 7.

She welcomed the development after initially feeling her complaint was not taken seriously.

Osteopathic council registrar Andrew Charnock could not say what the charges would be.

"The professional conduct committee will draw up the charges and a solicitor or a barrister will be appointed to prosecute on [its] behalf," Charnock said.

It could be "quite a few months" before the case went before a Health Practitioners Disciplinary Tribunal hearing, he said.

Tribunal senior executive officer Gay Fraser said the heaviest punishment a practitioner could face was deregistration.

The tribunal could suspend the practitioner's registration for up to three years, enforce practising conditions for up to three years, order a fine up to $30,000 and censure the person.

Cases were heard before a panel of five, chaired by an experienced lawyer, Fraser said.

Detective Senior Sergeant David Harvey said police investigated the woman's complaint but decided not to lay charges.

In October, the female patient said she saw the osteopath after her dentist advised her the toothache was caused by muscle tension.

The woman told the osteopath before treatment that she had struggled with depression since the age of 15 after a difficult childhood and abusive past.

She alleged the osteopath massaged her breast, through her clothes, for almost an hour, causing swelling and severe pain.

"I felt very uncomfortable but his words were reassuring and sounded legitimate. I told myself my discomfort was because I was just old fashioned and that I should stop being silly," she said.

Afterwards, she claimed she was told by the osteopathic council that the osteopath would have treated the "anterior fascia" of the chest, which was connected to the jaw.

The woman felt her case highlighted osteopathy guidelines were open to interpretation, which could leave patients vulnerable to exploitation.

The osteopathic council recommended procedures state that when sensitive areas are treated, clear explanations should be given, patients should be encouraged to bring a support person and the treatment should take place in a following appointment.

To practise in New Zealand, osteopaths must be registered with the osteopathic council, have an approved qualification and hold an annual practising certificate.