One lane is set to reopen on Bells Line of Road this week allowing drivers to travel in both directions at a reduced speed limit of 40 km/h.
Minister for Transport and Roads` Andrew Constance` said Transport for NSW crews assessed the road after it was damaged by last month's severe weather event, and are patching significant potholes between Bell and Mount Tomah.
"Drivers will be able to travel all the way from Windsor to Lithgow on Bells Line of Road without any closure points, but there could still be traffic delays in the area due to the changed conditions," Mr Constance said
"Crews are currently carrying out patching work and they anticipate the road will be able to be opened under traffic control within the next 48 hours, but the full reopen will still require a lot more time and technical investigations.
"Yesterday's geotechnical investigation revealed the affected areas are drying out and there's been no further damage to Bells Line of Road since last week.
"I am encouraging drivers to visit cafes, pie shops, apple orchards and other businesses along Bells Line of Road, because they are still open and need your support these school holidays."
Minister for Regional Transport and Roads, Paul Toole, said ground penetrating radar had been used to assess ground conditions beneath the road surface and help TfNSW develop strategies to restore access as quickly as possible.
"We know how important this road is both to locals and as a connection between Sydney and the Central West and we've been working hard to ensure it is safe to reopen," Mr Toole said.
"While there's still a lot of work to do to restore it to full capacity, we'll be working hard to keep communities up to date and connected."
March's flood damaged the ground underneath the road and caused nearby slopes to slip, leading to the road being closed between Bell and Mount Tomah for the safety of the community.
Further heavy rain could impact the stability of the slopes on either side of the road, requiring TfNSW to close sections of the road again to keep everyone safe. If this occurs, changes will be communicated to the community.
TfNSW acting deputy secretary, Howard Collins, said the current traffic control point will be moved from Berambing up to the Blue Mountains Botanical Gardens this week.
"This is good timing for the Blue Mountains Botanical Gardens as it means the gardens will be able to open to the public after finishing off their own flood clean-up operation," Mr Collins said.
"We are encouraging the community to visit the Bells Line of Road local businesses but make sure you add plenty of extra travel time because the road will be down to just one lane between Bell and Mount Tomah."