The government of New South Wales is investigating to make an 11-kilometer tunnel at upgraded Great Western Highway between Katoomba and Lithgow. This will be the longest road tunnel in Australia. The estimated investment value for the project is AUD 25 billion (US$ 19.33 billion).

This tunnel will be a link between the two tunnels for Blackheath and Mount Victoria with an aim to deliver a safer, more reliable connection through the Blue Mountains. Construction on the Great Western Highway Upgrade is expected to start at Medlow Bath in 2022, with the full upgrade to be completed within 8-10 years.