Grove Road murder: Auckland man Alan Hall's murder conviction quashed after 19 years in prison

Auckland man Alan Hall has won a 36-year battle to clear his name, with the Supreme Court quashing his murder conviction and accepting his innocence. 

"Thirty-six years of it, and here we are - final moments and we got what we needed for Alan and for the family, it's a win for the nation," Alan's brother Geoff said. 

On Tuesday the Crown admitted Hall shouldn't have been convicted because at the time police deliberately hid vital evidence from the defence and the jury.

In 1985 police went after Hall, accusing him of murdering Auckland father Arthur Easton, who was stabbed in a violent invasion at his home in Papakura.

At the time police said the evidence pointed to Hall and the jury found him guilty.

But investigations have since revealed evidence was intentionally altered and details were concealed from Hall's defence team.

The Crown now admits it was a "trial gone wrong" and a substantial miscarriage of justice.

"A miscarriage of justice is a miscarriage, never seen a case clear-cut as this one," Hall's lawyer Nick Chisnall said.

Hall was at the Supreme Court and heard the Crown accept its wrongdoing. 

"This court should quash and acquit Mr Hall and not order a retrial," a Crown prosecutor said. 

Chief Justice Helen Winkelmann told the court it is in the interest of justice to direct verdicts of acquittal. 

"We cannot end this judgement without acknowledging that just as the criminal justice system has failed Mr Hall, so too has it failed the Easton family."

Now Hall's legal team expects him to get the most significant payout in New Zealand's history.

"The next step we anticipate will be putting an application in for compensation," Chisnall said.