Māori women have led a protest on the eve of the country's national day, as New Zealand's would-be constitutional revisionist David Seymour delivered an incendiary address at the Waitangi Treaty Grounds.

New Zealand, which on Thursday marks 185 years since its official foundation, is reviewing the place of the Treaty of Waitangi in law, at Mr Seymour's urging.

The right-wing ACT party leader hopes to change the legal meaning of New Zealand's foundational document through the Treaty Principles Bill, currently before parliament.

Mr Seymour argues the treaty should be understood as giving all Kiwi citizens equal rights.

The generally-accepted interpretation, signed by Māori chiefs and the British Crown in 1840, is it affords Māori specific rights, including over natural resources.

The bill will not become law as ACT's coalition partners National and NZ First have pledged not to support it any further.

However, its tabling in parliament, along with a six-month public consultation, has generated historic backlash, including tens of thousands of Kiwis marching on parliament last December in the country's largest-ever protest.

Given his bogeyman status, Mr Seymour's presence at the Waitangi Treaty Grounds on Wednesday as part of an annual gathering of political leaders was always likely to generate angst.

Many Māori turned their backs and attempted to sing over Mr Seymour's speech, with someone even taking his microphone away in unfortunate scenes at the birthplace of the modern New Zealand nation.

In his speech, Mr Seymour attacked his critics and argued Māori should lift their aspirations.

"Here are some problems that you can't turn your back on because the numbers do not lie," he said.

"Māori home ownership. Māori school attendance. Māori crime victimisation. Māori unemployment. Māori incomes. Māori life expectancy ... none of it is getting better.

"If this is what a treaty partnership looks like, how is it working out for Māori?"

The following speaker, Greens representative Teanau Tuiono won laughs from the crowd as he followed Mr Seymour.

"I don't know how to follow that. The bar is so low I might need a shovel to get lower," he said.

Deputy Prime Minister Winston Peters - who hands over the baton as deputy to Mr Seymour in May under a power-sharing arrangement - said his NZ First party would not support Mr Seymour's law but he deserved better treatment.

Mr Peters said the "magic of the marae" included "a tikanga (practice) of respect where people could be heard out".

Speaking later to journalists, Mr Seymour said the Treaty Principles Bill delivered true equality.

"You can take away my microphone but you can't take away an idea," he said.

"The idea of equal rights is what the treaty promised and it's also what allows people to flourish."

In a break to recent practice, Prime Minister Chris Luxon was not at Waitangi for these discussions, opting instead to spend the national day on South Island.

At the same time as the gathering, Mr Luxon was 1000km away in Christchurch, announcing a road upgrade.

Opposition Leader Chris Hipkins attacked Mr Luxon for his Waitangi no-show.

"Christopher Luxon should have been here. The country is looking for leadership," he said.

Mr Hipkins said Mr Seymour was being deliberately provocative.

"He wanted a reaction and he got a reaction ... it's not the sort of thing responsible politicians do," he said.

Earlier in the week, New Zealand's Māori Queen - Nga wai hono i te po - made her first visit to Waitangi as the leader of the Kiingitanga movement.

The 27-year-old, who succeeded Kiingi Tuheitia following his death in August last year, was welcomed onto the Treaty Grounds in a ceremony featuring hundreds of participants in a mighty haka.

Ben McKay - AAP