A "deeply flawed" investigation into poor treatment suffered by a 92-year-old in a rest home shows the industry isn't properly watched over, her son says.

The Health and Disability Commissioner (HDC) today released a report into the care of Freda Love by St Kilda Care Home in Cambridge, after a complaint by her son Robert Love.

Freda Love, 92, died in Waikato Hospital in February 2017 after living at the Bupa NZ-operated rest home for five months.

Robert Love also complained to the Disputes Tribunal, and was awarded $10,000 against Bupa for a failure to provide a reasonable level of care. This included Freda being found shivering under a thin blanket in a urine-soaked bed in a room with the window open, and problems around her catheter, which was often leaking.

Today's HDC report found a number of "deficiencies" in care, including a lack of knowledge and skill by staff leading to incidents including the catheter not being secured. Bupa didn't provide enough education to staff, the HDC found, despite being aware of the ongoing problems.

Freda wasn't referred for wound care, despite review by a number of nurses, and temperatures at the facility weren't comfortable.

Love said the HDC hadn't considered his allegations that Waikato DHB and Bupa acted complicitly, or other incidents in which he said the DHB acted inappropriately.

It was "astonishing" the report found only one breach of the Code of Health and Disability Services Consumers' Rights, which was that care wasn't provided "with reasonable care and skill". He called the seven recommendations "mild and meaningless", including that he be given an apology, and provide the HDC with evidence of adequate staff training.

"There are a great many questions that arise from this enquiry and report. For me the paramount questions concern what we might expect from our regulatory authorities and in whose interests the commission works?" Love said.

"The real lessons that will be taken from this report, at least at a corporate level, is that you can still game the system - it already works for them."

Health and Disability Commissioner Anthony Hill said legal advice had been sought on Love's previous concerns, and the watchdog was confident its processes were thorough, fair and robust.

The HDC process follows principles of natural justice, and is impartial and independent, Hill said.

"We hear all sides of the story, consider carefully and make a decision. People will not always be happy with our decisions."

Bupa told the HDC it has since given "extensive" training to staff, including on wound management and catheterisation. Its chief operating officer Maggie Owens has previously said they had complied fully with the HDC investigation.

"We believe the handling of this complaint is consistent with the Health and Disability Commissioner's publicly documented process and the requirements as set out in the Health and Disability Act.

"This process balances the interests of all parties and ensures the fairness and integrity of both the process and the outcome of the investigation."

Love has called on Health Minister David Clark to investigate the processes used by the HDC. Grey Power and other groups want the Government to set up an aged care commissioner, something Labour campaigned on but hasn't actioned.

Associate Health Minister Jenny Salesa received preliminary advice from officials on setting up an aged-care commissioner over a year ago. That is still under consideration, she said, and a number of changes were being made to better protect rest home residents.

The NZ Aged Care Association doesn't believe an aged-care commissioner is needed, saying it would effectively replace the HDC, and that current complaints processes generally work well.