A 200-year-old bridge or multi-billion dollar tunnel. Can we just get two lanes?

But are we really about to go from a 200-year-old bridge to a multi-billion dollar tunnel?

Declaring the current highway has "stunted our growth out this way", passionate Great Western Highway critic Graeme Burke says a tunnel should have started years ago and he can't believe B-double trucks are continuing to use the convict bridge at Mount Victoria.

While Bathurst mayor Jess Jennings believes a tunnel cutting the travel time across the mountains down to around "30 or 40 minutes" would be a game changer for the Central West.

Many a motorist has seen the Great Western Highway's problems from the ground level, but Mr Burke can offer a different perspective.

A pilot for almost 40 years, Mr Burke has flown many people - including politicians - over the mountains and there's a very clear pinch point over the blue "ridgeway".

"There is no short-term fix [for the highway] because what in the name of god can you do through Blackheath?" he says.

"I've been a pilot for 37 years and I've taken [state Member for Bathurst] Paul Toole and a whole heap of them over there on a Sunday afternoon on a long weekend and just shown them: it's just absolutely chaotic.

"And there's no way around Blackheath."

The former owner of Bathurst company Burke's Transport and passionate Great Western Highway critic is more convinced than ever that the only way to solve the problems of the current road is to go underneath it.

"I think they've got to start boring," he said. "I really do. I don't think there's any alternative out of it."

Great Western Highway upgrades

Massive trucks continue to rumble over the almost 200-year-old convict bridge at Mount Victoria, which was built for bullock drays, he said.

"Now we're going over there with B-doubles that are grossing in excess of 60 tonnes.

"You get two B-doubles that meet in the centre of that bridge, one coming down and one going up, that's 120 tonnes across that convict bridge.

"I'm bewildered, absolutely bewildered, why it hasn't had a load limit put on it. I just can't understand it.

"I would doubt very, very much there would be another 200-year-old bridge on any national highway in Australia."

Mr Burke said both levels of government simply need to accept that the Great Western Highway is not adequate.

"It's really stunting the growth of the west as far as Bathurst and Orange and Dubbo and all of those places are concerned.

"I think truly it has stunted our growth out this way."

The previous NSW Coalition government's proposed Great Western Highway tunnel from Blackheath to Little Hartley was both underfunded and exceptionally expensive for what it proposed, Bathurst's mayor Jess Jennings says.

"There was next to no money in the federal budget for it and they [the federal government] were on the hook for, I think, over 80 per cent of the cost.

"It wasn't a very well-planned project for delivery and in the context of fixing the whole problem, it was a massive expense: $11 billion for 11 kilometres, I've got to say, never really rang true for me as being value for money when you recognise it doesn't solve quite a lot of the other pinch-point problems along there.

"For $11 billion, you'd really want to be getting an ultimate solution to the whole [Great Western Highway] strip."

But as Cr Jennings considers the highway stretch from Penrith to Lithgow, and its shutdowns and congestion, he says a tunnel might still be the solution.

"We need to get our heads around what is the trajectory of tunnel-boring costs. And I believe that that must be coming down - on a fairly steep decline.

"But the question is at what point does it become financially viable for us to look at tunnelling options, essentially from Penrith to Lithgow or Penrith to Hartley?

"I think we need to start exploring those sorts of options."

Cr Jennings said Tesla and Boring Company Elon Musk - the man behind the Vegas Loop - was asked on social media five years ago how much it would cost to build a tunnel through the Blue Mountains.

Mr Musk replied it would cost about $15 million per kilometre for the two-way tunnel, with an additional $50 million per station, taking the project to an estimated $1 billion.

People would not actually drive through the tunnel, though - their vehicles would be secured on platforms that could travel at high speeds between stations.

Any sort of potential tunnel under the Blue Mountains "opens up a whole new conversation", Cr Jennings said.

"Would it just be for passenger cars? Would it be passengers and freight? Could you do one for a train?" he asked.

"Even if you just took all the passengers off the Great Western Highway except for the residents who go there and visitors who want to go there, all of those towns from Blackheath down through to Emu Plains would become so much more peaceful."

The other aspect would be easing the squeeze on the Sydney basin, Cr Jennings said.

"If you did have a tunnel that got you through in about 30 or 40 minutes or something, think of the pressure release valve for Sydney on housing and infrastructure throughout the whole Sydney basin.

"If you could get from the CBD to Lithgow in 90 minutes - that's what people do from the Central Coast and Newcastle and Wollongong to Sydney on a daily basis - it changes the game massively."

Cr Jennings said the advances in technology are crucial.

"I'm very interested to get a sense and ... to understand what is the current tunnel boring equipment state of play and where is it headed and at what point would it become viable to look at the tunnel option?" he said.

"Because, really, I think in the long run, you're just going to get more and more traffic over the Great Western Highway over the Blue Mountains.

"It's only going to get more and more congested and doing patch repairs, year in, year out, is always behind the eight ball."

He said he has been travelling over the Blue Mountains since he was a child and the road has "always been playing catch-up".

"A tunnel is the only way to actually break that circuit," he said.

The NSW Government is continuing work on duplications of small sections of the Great Western Highway at Medlow Bath (worth $174 million) and Little Hartley (worth $232 million).

A more ambitious overall plan to duplicate the entire stretch of the highway from Lithgow to Katoomba has been shelved for the moment.

When she was in Bathurst before Christmas, state Regional Transport Minister Jenny Aitchison said the Federal Government's infrastructure review had put the east and west section duplications of the highway from Lithgow to Katoomba "completely on hold" and "what we're saying is that we are working with them".

"They want to do strategic corridor assessments and they have highlighted this as one that needs to be done," she said.