A new flyover interchange on the Great Western Highway at Coxs River Road - which is not far from where the Lolly Bug shop is located on the highway - is included in the design to upgrade the Great Western Highway to four lanes between Coxs River Road and the Hartley Cemetery.

The project will be the first phase of work carried out in the Little Hartley to Lithgow section of the Great Western Highway upgrade between Katoomba and Lithgow.

Together, the Australian and NSW Governments are investing more than $4.5 billion towards upgrading the Great Western Highway between Katoomba and Lithgow.

Deputy Prime Minister and Minister for Infrastructure, Transport and Regional Development Barnaby Joyce said the Australian Government is investing more than $110 billion in infrastructure projects across the nation.

"This section of the Great Western Highway upgrade will deliver a brand new gateway to the Central West," the Deputy Prime Minister said.

"This section is about 2.4 kilometres long and will provide two lanes in each direction to allow traffic to flow smoothly between the Central West and Sydney, potentially boosting tourism in the region which would generate new economic opportunities and jobs."

NSW Deputy Premier Paul Toole said Transport for NSW would begin early engagement with industry through a call for Registrations of Interest for the construction tender, while the Little Hartley to Lithgow Review of Environmental Factors (REF) is being determined.

"We are taking the time we need to consider all of the submissions carefully and will continue to develop measures to mitigate any potential impacts," Mr Toole said.

"We want to make sure we have done everything we can to protect the beautiful natural and cultural heritage of the Hartley Valley.

"Early engagement with industry will help us complete the tendering process as efficiently as possible without compromising the environmental assessment process."

"While we complete this work, pre-qualified contractors will be invited to register their interest in the upcoming tender process. Formal tenders for Coxs River Road will then be invited from shortlisted companies; however, no tender will be awarded until the REF is determined."

Federal Member for Calare Andrew Gee said the project will deliver a much-needed safety boost for motorists using this section of the highway.

"On busy weekends it can be very difficult for local traffic to get onto or across the highway, so this new grade-separated interchange at Coxs River Road will carry vehicles safely over the upgraded highway," Mr Gee said.

"The upgrade will separate local traffic from through traffic by realigning parts of the existing highway to create a service road. Intersections at Browns Gap Road and Baaners Lane will be upgraded, including construction of a U-turn bay on Baaners Lane.

"Crucial safety upgrades such as these will get locals and visitors to their destination quicker and safer.

"The Australian Government will continue to invest in and deliver the road infrastructure projects that matter to locals, tourists, businesses and freight operators."

NSW Minister for Regional Transport and Roads Sam Farraway said that the plans for an interchange are a direct result of consultation with the local community to ensure it delivers for their needs, as well as delivering a smoother, safer Great Western Highway.

"Transport for NSW has worked closely with the community for many years to build a new highway that will deliver a better, safer environment for local residents and all road users," Mr Farraway said.

"Improvements include three new acceleration lanes at Coxs River Road interchange and Baaners Lane, to help local roads connect safely to the new highway.

"A connection road near the Harp of Erin has also been moved further west to avoid impact on this heritage property, and the Coxs River Road overpass has been lowered to reduce its visual impact.

Road works on the Coxs River Road interchange are scheduled to start early in 2023, subject to planning approval.

For more information, visit nswroads.work/gwhd.