And while he's happy to see progress finally made, transport industry stalwart Graeme Burke said it still doesn't change the fact governments have historically dragged their heels looking to improve road connectivity between Sydney and the Central West.

"There's no question this tunnel will improve travel. If you look at the situation now, the major problem is Blackheath, so to bypass it with a dual-lane tunnel will ease congestion," Mr Burke said.

"But it's long overdue. I remember Ian Armstrong [former deputy premier and member for Lachlan] pushed for years and years to get the Bells Line Expressway up and running to no avail, and I was a big supporter of his vision."

For 30 years, Mr Burke has called for an alternative route though the Blue Mountains, calling the current Great Western Highway "nothing more than an extension of Parramatta Road."

"You can't really call the Great Western Highway a highway when it has 28 sets of traffic lights," he said.

The tunnel was officially confirmed by the state government on Sunday as the preferred option following an in-depth feasibility analysis and extensive investigation process.

Deputy premier Paul Toole said the proposed central tunnel would be Australia's longest road tunnel.

"The tunnel will reduce congestion and improve safety for local residents, tourists and freight operators," Mr Toole said.

"This is a complex and ambitious plan, but we're on track for shovels to hit the ground on the east and west stages of the upgrade early next year.

"The proposed tunnel design features dual carriageways for both eastbound and westbound motorists in separate twin tunnels and a gentler gradient to cut travel times and improve freight efficiencies."