When family, friends and colleagues gathered at his funeral, the tributes were not only for his policing career and his family life, but also for the tenacity he showed in fighting for the truth about the 1979 crash on Mt Erebus of an Air New Zealand DC10 sightseeing flight.

Greg, who grew up in Christchurch, was a graduate of the Gordon Hogg Wing 31. He began his career in Wellington in 1965, walking the beat with a whistle and wooden baton, and went on to lead the Team Policing Unit in the capital.

Speaking at the funeral, Inspector Paul Berry noted the respect that “the chief” was given by colleagues because of his strong values and leadership style. He shared some of Greg’s favourite stories, including when the TPU was called out to the Sinn Fein motorcycle gang HQ in Upper Hutt.

“On arrival, the team were warmly welcomed with a barrage of bottles and other projectiles. The chief was not happy about the lack of respect shown to his staff and the police. He called up a tow truck and instructed the driver to reverse up to and through the fortified fence. The good guys won, and the bad guys were arrested.”

Greg was admired for his honesty, strong sense of right and wrong and his passion for and loyalty to “the band of brothers and sisters who worked for him”, Paul said.

Greg’s operational skills were honed during responses to some of the country’s most serious incidents, including the sinking of the Wahine in Wellington Harbour in 1968 and the Sprott House retirement home fire in 1969 in which seven women died.

However, Paul said, it was his deployment to Antarctica as part of the Police team for Operation Overdrive, leading the recovery of bodies and evidence from the Mt Erebus crash site, which led to him “devoting years of his life to fighting for the truth to be told”.

“The long-standing grievance about the injustices to Captain Jim Collins and his flight crew consumed Greg, a man of principle who wanted the truth to be heard.”

Greg was sent to the crash site with the newly established Police Disaster Victim Identification (DVI) team to recover bodies. The fledgling team had met for a briefing mere hours before news of the crash on November 28, 1979, reached New Zealand.

Greg had never been on snow or ice, or to such a difficult or remote site as greeted the team in Antarctica. He arrived with two other officers, Inspector Bob Mitchell, who oversaw the operation, and Constable Stu Leighton.

As the officer in charge on the mountain, Greg drew up a grid for the site, covering 30 square metres in each segment, so the team of 10 police, assisted by four United States Navy photographers and a group of New Zealand mountaineers, could begin recovering the bodies.

It was during the operation that Stu Leighton found Captain Collins’ ring binder notebook. He gave it to Greg who sealed it in a plastic bag.

The notebook proved to be vital to the royal commission of inquiry led by Justice Peter Mahon, although Greg didn’t see it again until after the inquiry when he watched a television documentary in which Justice Mahon was holding the ring binder and asking a witness: “Where do you suppose the pages are?”

The pages that were gone from the notebook had contained coordinates for the flight.

Greg said he was “shocked” that the notebook had been tampered with because when he and Stu had seen it at the crash site, it was intact and contained technical writing that was clearly readable.

After having some difficulty convincing Police authorities, because the inquiry was over, that he had extra information to pass on, Greg met Justice Mahon who told him the contents of the ring binder were the flight coordinates, which “were incorrect”, that were given to Jim Collins at a pre-flight briefing.

In an interview at the time of his retirement in 2011 – as the country’s longest-serving commissioned officer after 46 years – Greg told The Dominion Post: “I now feel that if I had held on to it [the notebook], maybe none of this controversy would have occurred.”

His efforts in highlighting the issue of the missing pages were praised by Jim Collins’ widow, Maria. “He fought for us because he is honest to the last part of his being. Not being asked to testify at Justice Mahon’s royal commission of inquiry affected him. Thank God for a professional committed policeman,” she said.

After Erebus, Greg continued to work on operational roles around the country, including the hot spots of the Springbok Tour, the Marsden Point industrial action, and, in 1986, dealing with another maritime disaster when the Russian cruise ship Mikhail Lermontov sank in the Marlborough Sounds and the 700 survivors arrived at Wellington’s Overseas Passenger Terminal.

He always enjoyed being where the action was.

“The frontline is where the public want to see officers ensuring public safety,” he said.

He was Wellington area commander for four years and spent 15 years as the city’s emergency response manager. For several years he was also the Police Association’s Wellington region representative for commissioned officers.

Following his extensive operational background, Greg went on to plan and manage security for visiting VIPs, including heads of state.

He was made a member of the New Zealand Order of Merit for services to police in 2005 and awarded the Erebus Medal in 2007.

He is survived by his wife, Vivienne, two daughters and a son.