Council awarded a tender to construction firm Behmer and Wright at a price of $3.9 million.

Council had estimated the project cost at $3.2 million for construction plus a further $360,000 for furniture and landscaping.

Chief executive Dean Miller said Behmer and Wright's bid was $317,000 higher than estimated but council was able to fund the difference in its 10-year financial plan without sacrificing services.

The new offices will include environmentally-friendly features such as solar, eco-friendly building materials, energy-efficient appliances and rainwater harvesting.

Mr Miller said he was pleased the project received unanimous support from councillors.

He said the tender process was competitive, with seven applications received.

"This is probably one of the biggest decisions council has had to make," he said.

"We have been criticised for not consulting the public but this is not a community centre or recreational facility that lends itself to community consultation.

"We did consult with staff and they had some input into the design."

Mr Miller said council looked forward to the challenges ahead.

"This is a good environment to be building in," he said.

"There will be some disruption in the short term and we ask the community to be patient. Hopefully it won't impact too much on customer service."

Mayor Cliff Unger said while the project was unpopular with some shire residents, council had an obligation to act for the long-term best interests of all.

"We need a good facility for our officers to work in and the customers who come in," he said.

"Without a functional, efficient shire office, we will be in no position to provide essential services to our communities in the future.

"Contractors should be able to get going by the end of the month, all going well, so we will be able to see some results soon.

"It will take between 18 and 24 months to complete."