Thousands of people joined a march towards New Zealand's national capital on Friday after a contentious bill that would reinterpret the country's 184-year-old founding document passed its first hurdle in parliament.

Several rallies against the Treaty Principles Bill are being staged in towns across the country as a nine-day march, or hikoi, moves to Wellington. It is expected to reach the national capital on Tuesday.

An estimated 10,000 people marched through Rotorua, about 450 km (280 miles) north of Wellington, New Zealand police said in a statement. Protesters, some wearing traditional clothing, were greeted by hundreds waving the Maori flag and chanting.

On Thursday, Indigenous Maori leaders staged a haka, a Maori dance that was traditionally a challenge to opponents, at the first parliamentary hearing of the bill that seeks to redefine the principles of the Treaty of Waitangi.

Twenty-two-year-old lawmaker Hana-Rawhiti Maipi-Clarke ripped up a copy of the bill and led the haka in parliament as other Maori members and some visitors in the public gallery joined her.

First signed in 1840 between the British Crown and more than 500 Maori chiefs, the treay lays down how the two parties agreed to govern. The interpretation of clauses in the document still guide legislation and policy today.

The ACT New Zealand party, a junior partner in the ruling centre-right coalition government, last week unveiled the bill, which it had promised during last year's election.

The party has criticised the sharing of some governance matters between the state and Maori, arguing non-Indigenous citizens are losing out because of policies designed to uplift Maori.

But Maori and their supporters say the bill undermines the rights of the country's Indigenous people, who make up about 20% of the population of 5.3 million.

Coalition partners the National Party and New Zealand First are only supporting the legislation through the first of three readings. Both parties have said they will not support it to become legislation, meaning it will almost certainly fail.

Prime Minister Christopher Luxon reaffirmed on Thursday that his National Party would not support the bill's progress beyond the first reading.