That eye-watering figure was posed by Bob Barnard, the original designer of the Adelaide F1 circuit, in an interview with the ABC this week.
It was quickly rejected by South Australian premier Peter Malinauskas, before SA Motorsport Board boss Mark Warren doubled down on the rejection in an interview with FiveAA radio.
According to Warren there is currently no dollar figure attached to the project given the design phase is still in progress.
However he labelled the $100m prediction “excessive” given it is a remodelling of the existing circuit, rather than a ground-up build.
“I’ve not seen numbers like that,” he said of Barnard’s claim.
“I think that’s very speculative, especially when we’re still in that design phase.
“I think the other thing to remember is we are using a lot of existing road infrastructure, so that’s where we’ve got an advantage.
“We’ve got an existing circuit, and yes we’re going to do a variation of that circuit, but I think when we get through the design detail we’ll have a better picture of what the numbers are going to be.
“I’ve certainly not heard a number of $100 million, that seems excessive.”
The SAMB will add this new high-profile event to its portfolio in 2027 after successfully poaching Australia’s MotoGP round from Victoria.
The deal will see MotoGP break new ground with a street race in Adelaide, using a modified version of the circuit used by Supercars since 1999 that is heavily based on the original Adelaide F1 Grand Prix layout designed by Barnard.
Until now it has been unclear whether the MotoGP and Supercars events would share the same layout of city streets, given the proposed MotoGP layout robs the circuit of the famously high-risk Turn 8.
According to Warren there is no firm decision on whether the two categories will share a layout, or Supercars will revert to its more compact circuit.
However he did reveal that a shared version is the likeliest outcome, albeit with some changes between the MotoGP and Supercars events.
“Right now we are working with Supercars to go through the design,” he said.
“I think one thing with Supercars racing, it really does need to have that tight street circuit feel. That’s really what defines a lot of that and that’s what we’re looking to retain.
“So if we do end up agreeing to have it on the same circuit, which is looking likely, there will be modifications of the circuit between the events to tighten it up, bring the barriers in, things like that, to really retain that essence of what makes Supercars racing so fantastic.”
Environmental impact has been a big talking point around the MotoGP development, given the longer run off areas and corner profiles required for bike racing.
When asked if a number had been put on tree removal for the MotoGP circuit, Warren said the lowest possible impact was the ultimate goal.
“Not as yet,” he said of a tree removal figure.
“The design detail that we’re going through looks at minimising all of those impacts. We’re shaping it so that we avoid wherever possible impact to trees.
“So we’ve got a number of specialists around ecology and environmental arborists, we’ve got geotechnical guys, we’ve got lots of people on board to look at the best pathway to minimise impacts within the parklands full stop.”
The MotoGP redevelopment includes a complete rework of the Victoria Park section of the course, including a permanent pit building on the eastern side of the precinct.
This article first appeared on Speedcafe.com, a sister site to MotorRacing.com.