"We've been in a lot of homes that are totally the opposite," Mrs Swann-Cronin said.
The straw was sourced from the leftovers of a barley crop in the Wairarapa before being baled and sent to Rotorua.
The bales are stacked on top of each other and then trimmed with a weed eater before they are wrapped in chicken wire. They are then covered with five layers of plaster, leaving very few straight edges or corners.
It is built on a standard concrete pad with double glazed aluminium joinery and when finished will look like a normal four bedroom home, but with thick plastered walls.
The couple said it was a "moderately priced" home.
"A lot of the work has been done by us because you don't need to be a carpenter to stack bales - this has saved us a lot on labour costs," Mr Cronin said.
Inside, the couple have chosen exposed macrocarpa beams to be a feature in the main living room and plan to use a self-contained room for bed and breakfast accommodation.
The house is being built by Evan Crawford and his team from Straw Built Homes.
Mr Crawford said he had built six straw bale homes in the Rotorua district and had been building them for about 20 years.
"They are a high-quality home with much better attributes thermally and acoustically and have a much lower carbon footprint."
He said about eight tonnes of straw and 15 tonnes of plaster would be used on the build.
It was a lot more fun building a straw bale home than a regular house.
"We get to build - rather than assemble," he said.
Mrs Swann-Cronin said plenty of people had stopped to look at the property so they had decided to open it up to the public this weekend to help raise funds for Rotokawa School, where their two boys are students.
"Lots of people are interested in eco-building so this is a chance to take a good look before the plaster goes on."
* The open day is on at 24 Glenroy Place, off Brunswick Drive, tomorrow from 11am to 3pm. A gold coin donation for the school would be appreciated.
