Murrumbidgee Irrigation (MI) has finished one of its biggest water infrastructure projects yet.

Close to $50 million was spent for upgrades at Lake Wyangan, including replacing 17 kilometres of concrete channel, and installing 13 kilometres of new pipes and new outlets.

Executive Operations Manager, Matt Thorpe, has told reporters that the water to be saved could be in the hundreds of megalitres.

Beyond that, the exact amount will be unclear until the new Wyangan irrigation system has been running for at least a year.

“There's sufficient savings in water to actually generate the funding from the federal government to actually pay for it,” he told the ABC.

“So it's a good, almost (a) cost neutral exercise.

“We get the money to fix up our assets and the federal government gets the water back.”

The company said the big Lake Wyangan upgrade has provided a massive economic injection in the local area.

“It's been a fantastic for the region,” Mr Thorpe said.

“We probably peaked at a total of 715 different people being involved in the works.

“And where possible we've tried to access local contractors, so all the concrete has come locally.

“Some of the civil works contractors have also come locally, so it's been a big injection of cash for the local community.”

Mr Thorpe says it isjust the first part of a seven-year upgrade plan, which has another five years to go.

During that time Murrumbidgee Irrigation will spend $150 million on projects at Leeton, Bilbul, Hanwood, Yenda and Wah Wah.