As well as saving a category II historic building - it was built for the BNZ in 1910 and extended in 1957 and again in 1987 - the couple's other aim is to create jobs.
Ms Maxwell said the venture would employ about 17 people. She wanted to hire all locals if possible and was already talking with the hospitality training school in Paihia.
They planned a 12-bed backpackers and a cafe/restaurant on the ground floor with a five-room boutique hotel upstairs. As much as possible was being re-used or preserved, including the ornate ceiling, six fireplaces, grand staircase and native timbers.
"It's a heritage building so the facade can't be changed - but why would you want to?"
It would have solar panels, an electric vehicle charging station and as much local produce on the menu as possible.
The hotel would be called Left Bank, a word play on its former use, while the eatery would be the Mint Cafe.
With Kaikohe at the midpoint of the 85km Twin Coast Cycle Trail it is likely to be popular with cyclists, who currently have few accommodation options in the town, but Ms Maxwell believed there was a market for people visiting the healing hot springs at Ngawha.
They were investing a "significant amount" in the project and hoped to open by Labour Weekend.
"At this stage in life we don't really want another job, but it's time to give back," she said.
"There's lots happening in Kaikohe now, we're starting to see a turnaround. It's just the odd ratbag that drags the town down, there's lots of wonderful people who just need an opportunity."
Ms Maxwell said locals were carrying out the construction work and were a joy to deal with. Their costs were lower, they did a better job and were more willing to go the extra mile to preserve heritage features than big outside firms.
Mr Poutsma owns an accounting company while Ms Maxwell has been a farmer, Far North District councillor, meat processor and graphic design firm owner.