The planned route for a transport corridor through Western Australia's Midwest will bisect a wildlife sanctuary and threaten prime farming land and heritage homes, landowners say.

Landowners from Walkaway to Moonyoonooka say they are shocked and dismayed by the decision.

Main Roads and the state government are planning a transport corridor to divert heavy haulage and improve safety from Dongara to Northampton.

The chosen route will go into statutory planning documents with construction subject to future funding.

The plans were first released in 2020 and sparked community backlash.

The new plans affect fewer dwellings and address some environmental concerns, but the response has been similar.

Alana Birnie's children are the fifth generation to call their 1869 stone house east of Walkaway home.

The proposed "blue line" on the map sits 100 metres from the family's front door and runs over the sole water source for four properties.

"It cuts straight across the front paddock. It takes out our entire river frontage. It's just devastating," Ms Birnie said.

"It takes our whole existence here — it's our history, it's our everything.

Ms Birnie and her husband, Matt, were actively involved in earlier community consultation and said they were blindsided by the release of the new route.

"It was never even considered a possibility," Ms Birnie said.

"It wasn't on any maps — they had three options prior to this, and they've decided to add another one, obviously, but the other three have been discarded."

Wildlife rescuer Michelle Jones has established a conservation sanctuary and wildlife hospital on 73 hectares that also falls in the path of the proposed route.

She said she had no communication from anyone in regard to the proposed route.

"We had always known that the bypass road was going to go through around the Walkaway area and, when we did go and have a look, that was always going to be scheduled on the other side and never down the guts of the property we had purchased," Ms Jones said. 

Cut off from water source

Daniel Treasure farms at Moonyoonooka.

He said he knew nothing about the new proposal until a friend shared a map on Facebook after it was presented to parliament.

"We were just in absolute shock and dismay," Mr Treasure said.

"All of a sudden, it's another 2 kilometres to the east [of the previous plan] and heading straight through our farm."

Mr Treasure said it would effectively split off a large section of his farming property.

Transport Minister Rita Saffioti said the route had been chosen following extensive community and landowner feedback.

However, residents say consultations were only undertaken with those landowners affected by the previous preferred route. 

"I've visited Geraldton several times and met with local landowners who were concerned about the impact the original route would have on their properties," she said.

"I am pleased that we have taken on board community and stakeholder feedback and made changes to this route that will mean less impacts on local residents and the local community.

Mr Treasure said they had not heard from anyone and called a local councillor who was also in the dark.

"We don't know where to turn, what our options are. Has it devalued our land?" he said.

"Whether it goes ahead or not, we don't know. Whether it goes ahead in 35 years' time, ideas change as much as political parties, so it's just going to leave us in a limbo I think."