The terminally ill father of slain Aucklander Damien Loder Allen has called for those who know who killed his son to come clean.

As the 7-year anniversary of his son's killing nears, Mark Allen has told the Herald on Sunday he does not want to go to the grave without justice being served.

"I am desperately seeking ... to bring some sort of action, regarding the death ... of my son," Allen told the Herald on Sunday from his home in Thailand.

"After seven years no one has been arrested. I'm more than angry."


In February this year, a coroner's inquest into Allen's death concluded it was the result of "unnatural causes"

Coroner Matenga acknowledged the outcome had been "most unsatisfactory" for the dead 33-year-old's family and "the long time it has taken to get to this inquest is regrettable."

Mark Allen revealed he was terminally ill six years ago, suffering from chronic-aggressive hepatitis C as the result of a 1989 blood transfusion. He says his health has since deteriorated to the point where he believes he will be dead by the end of the year - and time is running out on his quest for the truth.

"There's no medicines, no cure, no treatment for what I've got. This year, in my mind, is the year I'm going to go," he said this week.

"My liver's coming to an end stage, maybe 20 percent function. On top of that I've got chronic fatigue syndrome. I'm pretty well housebound and have been on a disability benefit for about 17 years."

Allen says he does not want his health to be seen as "leverage" in his ongoing fight for justice - he simply wants to live to see the day justice is done.

"I just can't understand why this happened. Either there was a botch up in the investigation from day one, or they thought it was a wannabe gangster killed in a house with other wannabe gangsters and let it go."

Damien Loder Allen, 33, died of head injuries on September 24, 2009, in the house he lived in with three others in the suburb of Hillsborough.

Killed by blunt-force trauma to the head, no one has ever been arrested in relation to his death.

Fewer than 10 people were at the house on the night Allen died and police said at the time there were "obvious gaps in honest information" in what those people were telling police.

The house was owned by drug dealer Albert John Rhodes, who was the first person in New Zealand to be sentenced to life imprisonment for manufacturing and supplying methamphetamine.

Police told the Herald on Sunday this week the investigation into Allen's death remains open, but no staff are actually working the case.

"If information comes in, it will be assessed and a decision made as to whether it warrants further investigation," Detective Inspector Scott Beard said.

"Police would encourage anyone with any information that can assist in progressing the investigation to come forward."

Beard has previously said the "Operation Ebb" investigation was obstructed "by people who we believe are withholding vital information that would assist us and Damien's family to uncover the truth around what happened in the hours before he died."

Beard said a reward was considered when the probe was still active "however for operational reasons it [the reward] did not go ahead."

Acknowledging the upcoming anniversary of Allen's death, Beard said this "must be a particularly difficult time for Mr Allen's family and our thoughts are with them."

Police declined to release details from the police file to the Herald on the ground that the investigation is "unresolved and still an open case" and they "wouldn't want to prejudice any further investigations."