Residents in Blackheath have already been letter-boxed about a possible acquisition of homes to make way for the highway duplication.
Shocked residents of Station Street were disturbed to find leaflets in their letter-boxes late last week, before even the first public consultation on the matter.
Businesses, including Mitre 10 and the Hairloom salon, were also notified.
Erin Corscadden, owner of Hairloom and the building which houses 12 other businesses, said she was "devastated".
"It's a huge shock - I'm devastated actually. It's my livelihood.
"I just can't believe it, I can't believe they can just turf people out without any regard for their lives and businesses."
Some residents in Shipley Road also received leaflets.
RMS consultation sessions are due to start in Blackheath on November 27 but the townspeople will have their own meeting before that - tomorrow night (Thursday, November 21) at 7pm in the community hall.
The leaflets distributed along Station St notified people that the highway upgrade program between Katoomba to Lithgow had been announced.
"We are now in a period of public consultation. We are in the very early stages of design and planning.
"Your property has been identified in an area of interest within the corridor. Because we are in the early stages of the program, we are not acquiring property but we are investigating a strategic corridor area.
"If you would like further information or to speak to a member of the project team or make a comment during the public consultation period, then please do so on the details below."
A phone number and email address are then listed.
Some leaflets added a note - "Sorry we missed you" - but residents had not heard them knock; others, though, said they had spoken with those delivering the notices.
An RMS spokesperson said: "The Great Western Highway upgrade between Katoomba and Lithgow is in the early stages of planning. No decision on an alignment through Blackheath has been made.
"Transport for NSW recognises the complexity of the upgrade in this area and will continue to work with the Blackheath community to co-design route options and minimise impacts on property.
"Those residents and businesses that fall within the very broad strategic corridor study area have been contacted and are being encouraged to actively engage in the consultation process, which will shape the final alignment."
The RMS has four options for Blackheath: Duplicate the highway through the centre of town; bypass it beside the railway line (the Station St option), an outer bypass with bridges over Shipley Rd, Centennial Glen and Porters Pass, or tunnels under the town which would include ventilation stacks.
There are a number of heritage-listed buildings along Station St, including the station master's cottage.
The mayor, Mark Greenhill, said he was "appalled" that people were receiving the leaflets.
"I have already spoken about how we will see 30-metre trucks on our roads from Lapstone upwards with this state government plan. But right now people's homes and businesses are being threatened... I am so angry about this. I stand with these residents."