One patient died, while others were left with permanent injuries.
The tribunal found he stapled a woman's vaginal wall to her bowel, resulting in her excreting faeces through her vagina; he cut a major vein during keyhole surgery to remove an appendix; he cut a patient's aorta and damaged her spleen, which had to be removed, during an operation to correct reflux.
The tribunal ruled Dr Tonga's name should be made public and that he should be supervised for two years. Dr Tonga subsequently abandoned legal action to keep his name secret.
Dr Tonga worked at Grey Hospital from September 1994 to June 1997 and subsequently returned as a locum for brief periods.
The West Coast District Health Board has previously revealed he was the subject of four low level
complaints while on the West Coast. It said none of the complaints pertained to his surgical skills or required investigation by the Health and Disability Commissioner.
A Westport man, Hughie Bowe, 78, now deceased told The News three years ago that he was still suffering from Dr Tonga botching the removal of a benign tumour from his bowel at Grey Hospital 14 years earlier.
Mr Bowe said the operation went horribly wrong
after Dr Tonga accessed the tumour, which was near his anus, through his stomach instead of via his back passage.
Complications after the surgery meant Mr Bowe needed about 20 operations during 13 weeks in Grey Hospital, including five weeks in intensive care.
He suffered infection and a huge pelvic abscess. He went home with a colostomy bag (a pouch outside the body to collect waste), despite being told his surgery should not have required one. The bag was removed about two years later, but had to be restored after continuing bowel problems and infections.
Mr Bowe told The News in 2008 that he continued to suffer pain, bloating and bladder problems and could only stand for about 20 minutes before he suffered swelling and discomfort in his stomach.
I've been to several specialists in 14 years and the whole lot of them told me 'we can't do a thing because he (Dr Tonga) made such a hell of a mess.
Dr Tonga's surgical skills were questioned before the 2005 tribunal findings.
A Health and Disability Commissioner's report based on at least three complaints about him said a coroner had questioned Dr Tonga's competence in 2000 after a patient died of complications from a gastric reflux operation.
Dr Tonga failed to complete a required retraining scheme, set up in 2002 after two of the botched operations.
The Director of Anaesthesia at Timaru Hospital formally complained after Dr Tonga threatened an anaesthetist with violence during an operation.
