Former president of the Christchurch Returned Services Association and close friend Pete Dawson said Mitchell died surrounded by his family in the early hours of Monday morning.
Dawson said Mitchell was a sergeant in the air force's engineering service in the Pacific during World War II and had served in Guadalcanal.
"If anything comes to mind in regard to the likes of Bill and his fellow veterans of that era, is the saying we stand on the shoulder of heroes, we really do."
Mitchell had been an active member of the Returned Services Association since the day he was discharged following the war.
"The first thing he did after he left the Air Force at Wigram in Christchurch, was wander off to the Christchurch RSA for a couple of beers with his cobbers and joined the RSA and he's been a member of Christchurch RSA, right up until the day of his death as a life member."
The former Royal New Zealand Air Force engineer had led Christchurch's Anzac Day dawn service celebrations for a number of years in many different vehicles including a World War II American Jeep, a New Zealand Air Force Land Rover, on the back of a Harley Davidson trike and on a mobility scooter.
"He's a guy whose been out and gone for laps in V8 supercars, he's been up an aircraft, he's done so many things at his age - over 100, he was just an incredible guy.
"He was a wonderful guy and he'll be sadly missed by all his friends in Christchurch and the veteran community."
Mitchell gained the title as the oldest living World War II veteran in August, after fellow Cantabrian and war veteran Ron Hermanns died in August at the age of 109.
RSA Canterbury district president Stan Hansen said Mitchell had a tremendous life and had been a very active member of the organisation for 76 years which was a lifetime.
He said Mitchell was "a hard shot" and "a bit of a character" who would be sorely missed.
