Prof Robert Patman said the country had changed a lot over seven decades.
"One of the things I’m detecting early on is that the Queen’s passing may open a debate in this country about whether King Charles III should be head of state."
New Zealand had redefined itself over the last 30 years in particular, he said.
"There’s been a renaissance of indigenous language and culture [and] we tend to look to the Indo-Pacific, rather than Europe.
"New Zealand is finding its feet in international affairs — we’re in a world now where smaller and middle powers can play a bigger role than before, so we may feel less need to be under the umbrella of the Royal Family."
Debate about the role of the Royal Family would not reflect a loss of confidence in King Charles, but simply the changing times, he said.
A constitutional monarch, King Charles’ role was ceremonial as opposed to hands-on, so the impact of his accession should not be overstated.
As the longtime heir, he had plenty of public service experience and would likely "hit the ground running," and bring more energy to the role of monarch than his mother’s health had allowed in recent years.
He was also one of the first people in the United Kingdom’s public sphere to have brought attention to environmental decline, a stance ahead of its time, Prof Patman said.
Like his mother, who oversaw "disengagement of the British Empire and the decolonisation of large parts of Africa and Asia," King Charles was enthusiastic about the diversity of the Commonwealth, Prof Patman said.
"I think he’s very much like his mother in that he accepts that the Royal family can’t just carry on as it always has, the rest of the world is changing."
Although debate was likely, any change would have to reflect the will of the public, and would not be imminent.
Queen Elizabeth II had been an enormously popular figure who exuded calmness and stability, whereas King Charles was a "relatively unknown quantity" outside the UK.
"I don’t think [countries] will reach any hasty conclusions about Charles. I think he’ll be given a chance."