Magic Talk radio host Sean Plunket says the royal family are "an archaic bunch of German-Greek inbred toffs,'' adding they were responsible for the "carnage" of the Great War.
"They are not even British," Plunket said on his Monday show. "They are steeped in a class system as outdated as it is unfair.
"For goodness sake, they still believe in the divine right of kings; that the power of kings in somehow put upon them by God," said Plunket.
His comments come as Prince Charles and his wife Camilla embark on a six-day tour of the country, after touching down on Sunday afternoon.
Their official duties began on Monday morning with a wreath-laying ceremony at a war memorial in Mt Roskill.
The royal trip also includes a visit to quake-ravaged Kaikoura and the Waitangi Treaty Grounds.
In the wake of their tour, Plunket said it's time New Zealand ditch the royal family.
"They can go back to Britain; a country of which the family is not even native, and be [a] tourist attraction in Buckingham Palace, Balmoral and Windsor Castle," he told listeners. "We could have a president who lives at Government house in New Zealand that performs exactly the same constitutional duties that the Governor-General does and would lose nothing."
Plunket said this would make New Zealand a "truly independent nation".
"England does not protect us, the last people to protect us was the United States of America."
However, pro-monarchists argue having a head of state removed from the daily tumult of politics maintains stability and avoids partisanship.
Monarchy NZ chairman Dr Sean Palmer told Newshub Nation last year there was no guarantee a presidential office would be a positive change.
"It is easy to confuse more elections with more democracy," he said.
Prime Minister Jacinda Ardern thinks New Zealand will become a republic in her lifetime while former Prime Minister John Key has also said the country becoming a republic is inevitable.