The father of a motorcyclist who died after a crash believes hospital staff mutilated his son's body and stole his heart.

John MacKenzie has been battling for more than 25 years to try to expose what he claims is a coverup by Tauranga Hospital and other government agencies.

"They illegally mutilated his body to plunder and steal his heart," Mr MacKenzie told The Dominion Post.

"You'd be absolutely shocked out of your brain if you knew the extent they have covered this up."

Kenneth MacKenzie, 20, suffered serious head injuries when he crashed his motorbike in October 1987. He was taken to Tauranga Hospital, and died when life support was switched off the next day.

Despite his family refusing to authorise a transplant, his heart was removed and taken to Greenlane Hospital in Auckland, where one of its valves was successfully transplanted into a 16-year-old girl. It is unknown what happened to the rest of the heart.

Evidence given at a High Court hearing in Wellington earlier this month confirmed that Greenlane Hospital at the time "actively encouraged" mortuaries to send it heart valves for transplants, and that "it was not usual practice for consent to be obtained from next of kin".

Mr MacKenzie believes Kenneth's heart was removed at once, although the court judgment by Justice Robert Dobson, issued last week, says it could have been done 12 hours later during an autopsy.

Yesterday, Mr MacKenzie recalled walking into the intensive care unit and seeing his son's body dressed in a clean shirt. "I couldn't believe it. He just looked like he was asleep."

About an hour earlier, when other family members left the room, his son's clothing had been covered in blood.

Mr MacKenzie believes it was then that hospital staff went against the family's wishes by switching off life support earlier than requested and removing his son's heart.

"When I got there, the doctor was in my face and he wanted consent to take his heart. He looked blimmin' frightened when he saw me too.

"And now, when I think about it, I know why he was frightened. He was looking for retrospective consent."

According to the High Court judgment, which upheld an earlier decision to deny Mr MacKenzie civil legal aid, there was also "an issue" about whether a coroner actually authorised the autopsy and whether it was done to justify taking the heart.

Mr MacKenzie began making inquiries of Tauranga Hospital from 2002. In 2005, a Tauranga pathologist, Dr Beer, told him natural heart valves were often sent to Greenlane, but the heart remained with the body.

It was Dr Beer who said it was "not usual practice" to get consent from next of kin. "The logistics of confirming written consent . . . introduced a time delay that prevented the urgent delivery of the valve to Greenlane."

The rules were changed at the beginning of 1989.

Also in 2005, the National Donor Co-ordination Office in Auckland told Mr MacKenzie his son's death was before heart transplantation began in New Zealand.

However, the Heart Valve Bank confirmed it received Kenneth's aortic heart valve and it had been successfully transplanted into a 16-year-old girl.

Mr MacKenzie perceived that the inconsistencies in the explanations reflected an "intentional coverup of an unlawful taking of his son's heart", the judgment says.

He complained about his son being mutilated by the autopsy, and said the absence of his heart had deprived his family of "an opportunity to properly grieve and to farewell their son in circumstances of dignity".

He pointed out to the High Court that, when the practice of removing organs from dead babies and children at Greenlane came to light, their parents' claims were settled. However, he was still fighting to have his claims recognised.

Justice Dobson's decision says: "Mr MacKenzie considers that all government agencies he has dealt with have deliberately obstructed his initiatives to get proceedings under way, because they appreciate the extent of the embarrassment and/or cost involved for the Government if and when the courts recognise his claim."

Mr MacKenzie went to the High Court to appeal against a Legal Aid Tribunal decision to deny him legal aid to sue the Crown Health Funding Agency for damages. The agency denies any liability.

Among the reasons given for refusing legal aid is that court proceedings were filed outside the six-year claim period.