The family of Mark Anthony Haines has called for a fresh coronial inquiry to establish the truth behind his death 35 years ago.

Mr Haines, a 17-year-old Aboriginal boy, was found on train tracks 8 km south of Tamworth on 16 January 1988 and his family say investigations at the time have since been exposed as "completely inadequate".

Uncle Don Craigie said on Friday that after 35 years there are still no answers to his nephew's mysterious death.

"While the Country celebrated the 200th Bicentenary of Australia, our boy Mark was lying in the Tamworth morgue waiting for a second autopsy to be performed on him," he said.

"His family had to ask for this to make sure nothing had been missed. The investigation that was conducted into his death has been shown to be completely inadequate and we cannot get the answers or the closure that we need until this is resolved.

"This has taken too long; we needed this fresh investigation by the coroner to examine the evidence and all of the witnesses that are still around."

In November 2022 it was reported the NSW coroner would review Mr Haines' file.

Mr Craigie said that with a fresh coronial inquiry and subsequent investigations by the Tamworth Local Command and the state homicide squad, the family is "hopeful that those investigations may shed light on exactly what happened to Mark".

"We have been grieving for 35 years and we will continue to grieve for the loss of Mark," he said.

"We maintain that Mark has met with foul play. That was our position 35 years ago and subsequently, nothing has changed our minds. What we are seeking is the truth of what happened to Mark."

Mr Craigie thanked everyone who has stood with the family through "these many years in our struggle for the truth about Mark's death to be brought to light."

"We just want to know the truth of what has happened to Mark, our boy."

Sue Higginson MLC has backed the family's call for a new inquest.

National Indigenous Times has contacted the New South Wales government for comment.