Shadows have been cast over Adelaide's beloved Thebarton Theatre after the State Government's refusal to rule out its demolition to make way for the South Road upgrade.

Acting Transport Minister David Speirs has confirmed that between 600 and 1,000 buildings in the western suburbs could be compulsorily acquired for the "trickiest section" of the North-South Corridor road project.

He said a number of significant and heritage-listed buildings were in the mix.

"I'm not going to rule anything in or out," he told ABC Radio Adelaide's Breakfast program.

"But I acknowledge there are a lot of people in South Australia who have an affection for that building and others along that route."

The heritage-listed Queen Of Angels church in Thebarton is also at risk. ( Flickr: denisbin )

The risk to heritage buildings was raised in a NewsCorp article at the weekend, which also pointed out the Queen Of Angels and Holder Memorial churches were among those along the upgrade route, as well as the Maid of Auckland Hotel, two schools and a former Adelaide Electric Supply Company building.

Thebarton Theatre, a venue that regularly features national and international acts, was built as a town hall in the late 1920s and was inducted into the SA Music Hall of Fame last year.

Mr Speirs said planning was in its very early stages for the upgrade's stretch from Darlington to the River Torrens, and, with three models being considered, "two of them included a lot of tunnelling".

"If tunnelling were the option, that would see a lot less buildings acquired," he said.

"Technologies are continually changing and we do know that while tunnelling may have been ruled out five, 10 or 15 years ago, today it is cheaper and we've got better technologies there."

Calls to rule out demolition

When city apartments were given approval to be built near popular venues in the early 2000s, it led to the virtual destruction of Adelaide's East End live music scene.

An oversight in liquor licensing laws allowed new residents to make noise complaints that resulted in popular beer gardens being shut down and several venues closed.

When another iconic venue, the Governor Hindmarsh, was threatened by new apartments, it prompted a march on Parliament House and helped bring about legislative change.

An online petition has been set up to "Save Thebarton Theatre From The Bulldozers", and by early Monday afternoon had received nearly a 1,000 supporters.

SA Best MLC Frank Pangallo warned the Government that it would face the "wrath of massive public opposition if it dared" to demolish Thebarton Theatre or the Queen Of Angels.

He called on Premier Steven Marshall to guarantee the theatre's long-term future.

"It's one of the last remaining picture theatres of its type in Australia and has undergone extensive renovations to its magnificent interior and ceiling," Mr Pangallo said.

"It has entertained countless people in its almost 100-year history from film and theatre to pro wrestling and music."

Angels guitarist to 'vote for a tunnel'

The Angels guitarist John Brewster has been a regular act at Thebarton Theatre over his 49-year career, and said the venue meant "an awful lot to us, and an awful lot to South Australian music".

"Great bands have come out of South Australia and that couldn't have happened without venues like the theatre and all the little basement gigs round town back in the late '60s and '70s," he said.

"Thebarton Theatre played a huge role in that."

Thebarton Theatre has created memorable moments for many South Australians. ( Instagram: Thebarton Theatre )

The Angels, originally known as The Keystone Angels, played their first commercial gig supporting Cheech and Chong at Thebarton Theatre in what Brewster said was a mismatched gig.

"They [the crowd] threw Minties at us," he laughed.

"They hated us. It was very hippy days.

"On a more serious note ... once these places are gone, they're gone, and I think it's very important to try and preserve them.

"I'd vote for a tunnel underneath."

Mr Spiers said he had his own memories involving Thebarton Theatre and, as "heritage minister" would be talking to his "colleagues about the importance of doing our best to protect those buildings".

In the name of progress?

Opposition transport spokesman Tom Koutsantonis said it was important to talk with design engineers early in the planning stages, along with the Federal Government, to ensure significant buildings were protected.

"They've put out to tender the construction of this road and they've asked the consortium that are building it to design it," he said.

"The consortium are interested in their investors and their shareholders and will go the cheapest, fastest direction they possibly can.

"It's important that we get the Prime Minister and the Commonwealth Government involved in this conversation, because the state does not have the resources to save these iconic buildings."

Mr Koutsantonis said he considered the theatre and the Queen Of Angels church to be "iconic landmarks".

"Ministers like Stephan Knoll, David Speirs and myself come and go, but these landmarks remain," he said.

"We have to ask ourselves, are we prepared to give this up in the name of progress?

"We need to have that discussion now."