The day will run from 11am to 4pm at Pakaitore/Moutoa Gardens, with bands, solo acts and dancers. There will be kai and information stalls, a childrens' area and a dedicated space for people who want to ask about the Treaty.
Patea's Paepae in the Park had its biggest crowd of about 5000 on its 10th anniversary, organising committee secretary Mareta Marsters-Grubner said.
This year it will start at 9am with a pōwhiri. South Taranaki Mayor Ross Dunlop, former Whanganui MP Chester Borrows and current Whanganui MP Harete Hipango will be among the speakers.
After that there's a cup of tea in the Patea Old Folks Hall, followed by a whole series of entertainers. They include Monique Matthews, the Arakanu Marching Team, Harmony Showdown, Boss Heke, Unity Jayne Wara, Reset and Selah Saints.
The line-up will be less reggae-oriented than in the past.
"The committee wanted more variety, to cater for children, families and the elderly," Mrs Marsters-Grubner said.
The Patea Māori Club, always a drawcard, is on at 12.30pm and after that a 15th anniversary cake will be cut.
There will be a free bouncy castle for children, and a creative art activity in a tipi. There will also be about 40 stalls, many selling food, and lots of spot prizes.
X-Factor semi-finalist Taiaroa Neho is the master of ceremonies, an ATM will be available at the Four Square store and the event will go ahead rain or shine, Mrs Marsters-Grubner said.
Commemoration of the day has taken many forms in the 178 years since the Treaty of Waitangi was signed by Māori chiefs and representatives of the British Crown.
February 6 is now regarded as New Zealand's founding day.
Its first commemoration was in 1934, and it became a public holiday after 1954. It was called New Zealand Day for a while, but reverted to Waitangi Day in 1976.