A poll commissioned by a pro-republic campaigners shows the majority of those surveyed would prefer a Kiwi as the next head of state.
But the head of Monarchy New Zealand is questioning the result, arguing New Zealand would be better served sticking with the Windsors.
For the second time since 2016, the poll conducted by Curia Market Research on behalf of the NZ Republic campaign showed a greater favouring of republicanism, though the number had dipped slightly since the last poll.
Overall 56 per cent of those asked said they'd prefer a Kiwi in the role, down from 59 per cent in August 2016 but up from 44 per cent in June 2014 and 47 per cent in April 2015.
The overall number was reached by combining responses from those saying they would like an elected head of state (45 per cent) or one selected by two thirds of Parliament (11 per cent).
38 per cent said they would like the next head of state to be a British monarch, up from 34 per cent in 2016.
A small fraction were unsure.
The poll was carried out in the buildup to last week's royal wedding, with 930 respondents surveyed.
"The latest poll results show support for the next head of state to be a New Zealander is still in the majority, 18 percentage points clear of support for the British Monarch" a campaign spokesman said.
Support for a republic was favoured by more than half of all age groups except those in the 61 and older bracket, where support dipped to 49 per cent.
However, even in that case the number was higher than support for continuing the monarchy, with 46 per cent in favour and 5 per cent undecided.
Young people in particular support a New Zealander as head of state, with nearly three quarters of the 18-30 year age group supporting the transition.
"The results are very encouraging given the amount of media coverage the royal wedding had," the spokesman said.
"The majority of Kiwis understand that watching royal celebrity events and wanting a New Zealander as head of state are not mutually exclusive. You are allowed to do both."
However, Sean Palmer from Monarchy New Zealand said it was misleading to combine responses favouring a Kiwi head of state.
Those who wanted a democratically elected head of state might favour continuing the monarchy over Parliament deciding and visa versa, he said.
Calling the republic campaigners "out of touch", Palmer said republicanism was an out of date, 20th-century idea.
"We live in a modern interconnected world that's constantly shrinking."
With Brexit on the horizon, the UK was desperate for allies and New Zealand should make the most of their Commonwealth connection.
"We should be building on that relationship, not trying to destroy it," he said.
"When I'm speaking to young people, that's the thing they're concerned with - how is New Zealand going to fit into the modern world."
Recent attention to Prince Harry and Meghan Markle's wedding and the joy in New Zealand at Prince Louis' birth showed interest in the Windsors was anything but waning, Palmer argued.
"There is no indication of New Zealanders losing their interest or association with the monarchy."