As he prepares a celebration of his son's life on what would haven been Joseph's 21st birthday, Dunbar said he would never give up the battle to recovery his son's body.
"I will fight to my last breath to take Joseph home. No one is going to stop me doing that," he told the Herald on Sunday.
"He was just a little boy. He was a child ... 17 years and one day old."
It had been hoped that a re-entry into Pike River's drift - the 2.3km tunnel leading up to a rockfall caused by explosions deep in the mine - could have been done this year.
But ongoing delays have infuriated the Pike River Families group. Those feelings have intensified after the release of the re-entry feasibility study on Tuesday.
The men's remains are still entombed in the mine, despite the Govt announcing more than a year ago it would fund a re-entry of the mine. Photo / NZH
Solid Energy chairwoman Pip Dunphy said on Wednesday the state-owned energy company understood the lack of progress was "frustrating", but it was imperative that "industry best practice" was followed to reduce the risk of death or serious injury to the body recovery team.
Dunbar said he feared Solid Energy would rule it would be too unsafe to enter the mine without a technically, geographically and financially challenging second tunnel.
"What I want and what my family needs is if Solid Energy are not going to go in, then tell us. Don't dick us around for another four years. Just tell us, be honest and be honourable," he said.
"I am telling you, there is evidence and a high probability that there is [men] in there [in the drift], sitting, sucking on self-rescuers that would have not only been brought home for burial, but would have survived and still be walking among us today."
Dean Dunbar said the family hoped plans to commemorate Joseph's short life would include the opportunity to camp in the Pike River compound on the eve of the tragedy.
"We will sit down and talk about what sort of a 21st we can have, without making it too much of a sombre day for all," he said.
"We don't want to put our burden on other people. I think there are enough people suffering here as it is. Because his birthday is the day before he died we can run those two days together and maybe Solid Energy will let us nestle in at the main administration block for a day or two."