Teams of 30 pupils from five classrooms each take a turn running the restaurant, while their teacher acts as head chef, he said.
Brock said invited guests paid what they thought was fair for their three-course meal and the menu changed daily as the next class took over running the restaurant.
The restaurant, which opened on Monday and runs until November 2, had already made $725 on its first day, with the money raised paying for surf lessons next term.
Brock said this was the second year the school had launched a pop-up restaurant aimed at expanding the children's learning and life skills.
Most of the children were foodies and regular watchers of food programmes such as MasterChef, and they relished the chance to be involved.
Classmates Parav Saily, 9, Jack Crozier, 10, and Tayla Holton, 9, helped greet guests and with some of the cooking. They were buzzing.
Jack said he had wanted to become a chef since he was 6 and being involved in Ngaru had inspired him to work hard to achieve that goal.
Tayla, a fan of the Great Kiwi Bake Off TV programme, said she had "loved the whole experience".
Among the invited guests were Fletch, Vaughan and Megan from ZM Breakfast show
Vaughn said he was impressed by the children's hospitality and cooking skills.
"We could be talking about the next top restaurateur or next Gordon Ramsay, although I haven't heard any swearing coming from the kitchen," he quipped.
Guest Kaywyn McKenzie said: "It's amazing. I haven't had this kind of service for a long time. The children are so highly organised and attentive, and the food was great too.
"I think it's really great to see the school thinking outside the box to enable the children to learn these sorts of life skills which can be transferred to other parts of their lives."