Ngai Tahu is developing a multi-million-dollar high-tech water ride in Rotorua that plans to take up to 500 tourists an hour through the ecological evolution of New Zealand and finish with a 12m splash.

"Always got to have a big splash at the end," said Rainbow Springs Kiwi Wildlife Park project director Stewart Brown.

The $10 million-plus project at the park will include an outdoor 400-seat free-flight bird-show auditorium, interactive playground and reptile enclosure.

The water ride would aim to tell a story that educated people and encouraged action on environmental issues.

"This will certainly stand as one of the larger developments in New Zealand's tourism history," Brown said.

The ride would take visitors back to New Zealand before the arrival of humans and travel nearly 500m, with life-size animatronics including a Haast's eagle attacking a moa. "[The] Haast's eagle was the biggest flying predator in the world at that stage, [its] wingspan was over three metres," Brown said.

"It was quite feared when Maori first arrived."

Visitors will travel through the arrival of Maori and Europeans, including a depiction of a village and tree-felling.

Then in a cave the nearly 6m boats will be lifted 12m to travel through the tree canopy before dropping into a large splash pool. Brown said the main planning was completed and the development, the biggest single investment since the park started in 1932, was expected to open early next year.

The initial planning was for a capacity of 500 people an hour, with an ability to extend.

The cost was being met by Ngai Tahu Holdings, the shareholder of Rainbow Springs owner Ngai Tahu Tourism.

Ngai Tahu Tourism chief executive John Thorburn said the development was great news for Rainbow Springs and the whole of Rotorua as a tourist destination.

"The development will heighten both domestic and international interest in the region as a place to visit," Thorburn said.

"Ngai Tahu Tourism is investing for the long term.

"As one of the integral hearts of New Zealand tourism, with its strong culture and New Zealand history, Rotorua is a key focus for us."