The Lower Hunter Freight Corridor, as the project has more recently been known, has been discussed for decades but until Monday was little more than a broad line drawn through Lake Macquarie and Newcastle's western fringes.

Documents released on Monday show how the proposed line would skirt existing built-up areas in West Wallsend and Cameron Park.

The dedicated freight route would alleviate pressure on the existing rail line through suburban Newcastle and free up congestion at the Adamstown and Islington railway crossings.

Regional Transport Minister Paul Toole said it was critical the corridor was secured before the freight task increased and urban sprawl swamped available land.

"The plan to separate the majority of freight and passenger rail services between Fassifern and Newcastle will increase the efficiency and reliability of the rail network for both freight and passenger services, and help businesses and industry move freight more efficiently, supporting growth across the Hunter region," he said.

"With the NSW regional freight task expected to increase 12 per cent in the next 15 years, we need to ensure land is available to deliver essential freight rail infrastructure, in the future, and when it is needed.

"We also recognise that if we don't identify a suitable corridor location now, forecast population and urban growth in the Hunter region will make it difficult to secure a corridor which connects to Hexham.

The majority of land on the proposed route is government-owned, but landowners who may be impacted will be contacted by Transport for NSW.

Community consultation about the route is open until August 17.

Feedback can be provided online.

The agency's Future Transport 2056 Strategy, released in 2018, identified the Lower Hunter Freight Corridor for potential delivery in the next 10-20 years.

More to come.