Mr Wulff believed the agricultural park could become a tourism destination, competing with Waitomo Caves, and the Agrodome and Te Puia Maori Arts and Crafts centre in Rotorua.
"We are working with an operator to put the farming sheds and Hall of Fame together and to collate the whole history of agriculture," he said. "This hasn't been done before, and it's the missing link in tourism ventures.
"There hasn't been anything new since the bungy jumping, and we can attract busloads of tourists to Putaruru, which is very accessible," Mr Wulff said.
He said there was a definite need for a medical centre in Putaruru and new supermarket, the only one being a smaller Countdown store.
"The good thing about the plan is that each part, or activity, is independent of each other and can move forward based on demand."
Buttermilk has been designed into four areas - 15,000sq m retail park, 4000sq m auto park, 14,000sq m trade park, and 9800sq m agri park.
There will be room to test drive new farming equipment.
The investors are relying on a catchment of 16,000 farms within an hour's drive, Putaruru's own population of about 4000, and up to 10,000 motorists a day travelling through the town on the main state highway.
Mr Wulff said the proposed development had already changed the feeling of the town for the better.
The sawmill and processing plant, first established in 1903, was closed by Carter Holt in 2008 with the loss of 212 jobs.
The investors bought the large site last year. They have asked the South Waikato District Council to include the proposal in its revised district plan.
Mr Wulff and Mr Macfarlane first met 20 years ago when they each set up their furniture factories - Mr Wulff Heirloom Furniture and Mr Macfarlane Design Mobel.
Mr Washer, a Sharp Tudhope partner, has been their lawyer.
Mr Washer and Mr Wulff are shareholders in the new Sharp Tudhope building being built on the corner of Devonport Rd and First Ave in central Tauranga.
And Mr Macfarlane and Mr Wulff previously teamed up to develop a 2.5ha business park in Waiuku - it's half completed.
Two years ago Mr Wulff converted a Briscoes store in Rotorua into a medical centre.
Asked how they came up with the name Buttermilk for Putaruru, Mr Wulff said: "It's the liquid left over to make butter once the cream has been flogged.
"When Graeme Hart bought Carter Holt he flogged the cream and sold off the buttermilk. That's what happened to Putaruru."