Authorities are urging heavy vehicle road users and tourist groups to avoid travel across the Blue Mountains on Wednesday.
Non-critical travel on the Great Western Highway between Penrith and Lithgow should be avoided between 6am and midnight as conditions could worsen with little notice.
All long and wide load permits have been revoked.
The Bells Line of Road is closed.
Motorists are asked to consider alternate travel arrangements or delay their journeys until otherwise advised.
Please take notice of advice on variable messaging signs and give way to emergency service vehicles.
Blue Mountains, Lithgow and Oberon Tourism chairman Randall Walker has also recommended tourism operators avoid the Blue Mountains.
Mr Walker has recommended accommodation providers defer bookings.
"The risks we face over the coming days should not be underestimated," he said.
"It is our paramount mission to ensure that no visitors to our region are injured due to bushfires."