Transport for NSW A/Director West Alistair Lunn said preliminary work for the $200 million flood proofing project will investigate the section of the Newell Highway from Compton Road in West Wyalong to Hereford Street in Forbes.

"The Newell Highway extends from the Queensland border to the Victorian Border and is the backbone of the freight industry in NSW," Mr Lunn said.

"The NSW Government recognises the importance of improving flood immunity on the crucial section of the highway between Forbes and West Wyalong, for the benefit of all road users."

Until early December, environmental specialists will be gathering information to inform the Preliminary Environmental Investigations.

This work includes reviewing existing flood studies and preliminary identification of flora and fauna species along the length of the project.

After the Preliminary Environmental Investigations are complete the next steps in the project will be to progress the strategic design that will include more extensive consultation with landholders and key stakeholders, further field and data collection and flood analysis.

Mayor Phyllis Miller OAM said it was "essential" the flood-proofing works be done as quickly as possible.

"The last flood closed our economy for over six weeks and we cannot afford for this to happen again," she said.

The promise of $200 million for flood-proofing works came in the lead-up to the NSW elections in March last year.

The West Wyalong to Forbes section of the Newell Highway was closed, due to flooding and the resulting damage, for six weeks during the 2016 floods. The repairs cost $1 million.

Transport for NSW says it will keep the community informed as the floodproofing project progresses.