Entry is from Burnside Ave. It's free, and there will be seats provided.
Catering will be done by Patea's Red Rock Cafe, with an $8 breakfast available from 6.30am and hot lunches at midday.
There could be about 50 people watching the action through the days.
"We really, really love to have spectators there," says Brenda
The championship is known for its goodwill and camaraderie.
"It's the best show trial in the country. Anyone who goes to it tells you they just break their necks to come back."
On Friday and Saturday dogs will be worked from 7.30am in the morning until about 5 or 6pm. The finalists compete in a run-off on Sunday morning, to be filmed by Country TV.
For competitors, entry costs $22 per dog. The total prize pool is $3400, plus product, and there is also a Bruce Harvey trophy. Every competitor will get a prize.
The judge, Chris Baker, is from the King Country.
The organisers have also given to a charity each of the last few years. This year they plan to give $3000 to St John Hawera.
One aim of the event is to encourage new and young people into dog trialling as a competitive sport. Another is to show people the skills needed to work a sheep dog.
Entrants come from all over the North Island. This year they include 26 women with 51 dogs, and a man from Pukekohe who trains zoo animals. Both trainers and dogs will compete in categories - first novice, then maiden, intermediate and finally open. Any dog can win - an intermediate-level dog was the overall winner last year.
Whanganui triallist and dog trainer Brian Burke will be competing, along with Paul Evans and Paul Green, Philippa Lambourn from Mangamahu, and Merv Williams and Kathryn Oliver from Raetihi.
One of the younger competitors will be Whanganui's Peter London, with two dogs. Another is Erin Ball, from Northland, who began competing as a child and has now reached intermediate level.
The 300 sheep needed will be provided by Hawera's Brewer family. They will each be used twice, and will be worked with a dog at a Manutahi farm before going into the ring.
Brenda says sheep not used to dogs could go "barmy" when they first encountered them.
"They bolt everywhere. We've got a lot of novice and maiden competitors so we want everyone to have a fair crack at it."
The event started eight years ago. Taranaki dog triallist Graeme Northcott began it, with the help mainly of Waverley triallists. Brenda has been involved from the beginning and will be competing this year.