John Minchinton suffered serious, ongoing injuries when he was bashed in an early morning workplace robbery in 2010.
Now ACC officials are trying to deny him funding for medical treatment for injuries because there is some evidence the injuries are caused by "degeneration".
The corporation last night declined to comment on the case because it had not been able to access Mr Minchinton's privacy waiver, which he left on the voicemail of his case manager who finished work at 2pm.
At 6.45pm, the Herald proposed alternative means of obtaining a waiver from Mr Minchinton, who couldn't provide one quickly by email, but ACC said it was too late as its staff did not routinely work in the evenings.
Mr Minchinton, 58, of Wattle Downs in South Auckland, yesterday recalled the terrifying attack in East Tamaki in June 2010 which knocked him out.
"They used a piece of wood or steel. They hit me across the back of the head and neck and then they tied me up. I was found with an air-hose around my legs and my neck."
The police have not found the offender, although DNA samples were taken.
Mr Minchinton was found unconscious about 45 minutes after the attack and was taken to Middlemore Hospital with injuries to his head, neck, leg and back.
"I've had an operation on my knee; that's been treated and was done reasonably well. The rest of it's ongoing. I still have headaches, pain in my neck and shoulders, back and side... I have numbness that starts around the middle of my back and runs down one side and down my right leg."
"Now [ACC] are starting to call it all degenerative. I've been to a musculo-skeletal specialist... I was sent there by ACC. His report says there are some degenerative problems there.
"The problem I have is before the incident I didn't have the headaches... the pain, the numbness. I've had previous injuries to my back and neck. They have been sprains which have resulted in maybe one day off work."
But these had been nothing like his current injuries, which had caused him to lose his job because it was impossible to work full time.
He receives ACC earnings-related compensation but says the corporation has demanded he hand over a workplace pay-out of more than $11,000 - a month in lieu of notice and unused annual leave, accrued mostly before his injury.
"When you have a big mortgage, continuing health issues... very little likelihood of getting employment... I find it hard to understand the system."
RULES TWISTED, SAYS LAWYER
The ACC publicly misrepresents the wording of its rules on degeneration, claimants' supporters say.
"They just [need] a sniff of degeneration ... and it's goodnight nurse," says leading ACC lawyer John Miller.
The Accident Compensation Act 2001 permits ACC to decline cover for an injury on grounds including that it is caused "wholly or substantially" by ageing or by a non-work, gradual process. "Substantially" is not defined in the act but has been interpreted by the courts as at least 80 per cent. But ACC's public statements repeatedly turn this legal test on its head.
On Monday, the corporation said: "ACC's legislation specifically states that the need for surgery must be 'wholly or substantially' caused by the injury, and clearly excludes personal injury caused by the ageing process or gradual process, unless work-related."
Mr Miller said: "The act doesn't say that at all. It's applying the wrong test. It's loading the dice in their favour.
"They are cutting people off for 'degeneration' up and down the country. They don't even go for 'wholly or substantially'... It's a really hard-nosed insurance way to go."
Claimant advocate David Wadsworth said the error was partly due to ACC's relying on medical advisers for both a medical and legal decision.
An ACC spokesman said the corporation could not comment on this matter until today.