The Olympic-standard course will also be used by the Fire Service, Search and Rescue and Coastguard for frontline training. The park will adjoin the Vodafone Events Centre on Great South Rd, Manukau.
Ferguson, who won four Olympic gold medals and one silver, helped to drum up support for the project, which "took a while", he said.
"It's going to be an amazing course ... when kids come and see this, they'll just want to jump straight in."
He said the course will be safe, and a push of a button would turn off the machines that create the whitewater.
Beginners could start the course on "a trickle" he said, and gradually build up confidence.
He said there would "undoubtedly" be Olympians developed at Wero Whitewater Park.
"Within 10 years there'll be kids who haven't kayaked [before coming to Wero] on our Olympic team.
"It's something I've always wanted to do. I made a difference in [canoe] sprint racing ... now I can make a difference ... by helping facilitate others have fun."
Prime Minister John Key turned the first sod at the development site yesterday and said the Government had backed the project because of the benefit to young South Aucklanders.
"It's a really important facility for building confidence for young people. They'll be the bulk of people that come through."
He applauded Sir Noel for doggedly pursuing the Government's support for the project.
He said he hoped Olympians would come through the facility and he was "really keen" to have a go in the rapids himself.
The first international sporting event held at the park would be the 2017 World Masters Games.
Stage 2 and 3 of the project would include a building for changing rooms, storage space and retail space, a Te Papa exhibition about the human body, an art gallery, cafe, and classroom spaces.
Stage 4 would be an interactive visual display telling the Polynesian story of journey and stage 5 would be an artist in residence and gallery project.
Wero Whitewater Park
• Great South Rd, Manukau.
• Will include Olympic-standard whitewater course, learner grade course and a 4.5m water drop.
• Cost: $37.5m.
• Scheduled to open early 2016.