A Canterbury doctor who had sex with a teenage patient 25 years ago can continue practising and keep his name secret.

However, he has been censured by the Medical Practitioners Disciplinary Tribunal which fined him the maximum $1000.

The GP was also required to be mentored by a health professional for three years and ordered to pay $62,666.86 in costs.

The tribunal found the doctor guilty of disgraceful conduct in June.

A complainant known as Ms A became a patient of the doctor at 13, and later babysat his children, The Press reported.

She was raped at 16, and her mother went to the GP for help.

A sexual relationship developed with the doctor and lasted for about three months in 1985.

Ms A told two female friends and a counsellor about the relationship, but otherwise kept it secret until 2001, when her opinion of the relationship changed.

She lodged a complaint at the (Health and Disability) commissioner's office.

The tribunal in its decision said there was no evidence the doctor had behaved inappropriately before or since.

It said the "proved conduct of the charge (was) entirely out of character" and granted the doctor permanent name suppression.

Ms A criticised the penalty as lame.

"The argument seems to be that seeing as he got away with it for so long, he might as well get away with it forever."