Jones, 25, is driving the squad’s #18 Chevrolet Camaro steered this season by Mark Winterbottom.
Team 18 has both cars at the circuit, with David Reynolds driving its #20 Tradie Beer entry as part of a Supercars category test that also involves Thomas Randle in the #55 Tickford Mustang.
Jones has raced Porsches in Australia and internationally for the last six years and is excited about his Supercars chance.
“Having been a fan of the Supercars series for as long as I can remember, today is a pretty special day getting my first taste behind the wheel,” he said.
“I’m very grateful for the opportunity Charlie [Schwerkolt], Adrian [Burgess] and the entire crew at Team 18 has provided and excited for what the future may hold.
“There will be a lot to learn today, and I’ll be using every bit of my experience in the sport to get up to speed as quickly as possible.
“I’ve spent countless hours on the sim preparing and I’m confident it will be a productive day.”
Team principal Burgess expressed a desire to include Jones in the squad’s future plans.
“We’re excited to have Harri join us for this evaluation test,” said Burgess.
“He’s demonstrated immense talent in multiple categories and has a proven track record of success here and in Europe.
“This is a fantastic opportunity to see how his talents translate to the Gen3 Supercar, and we’re looking forward to seeing what he can do behind the wheel of the DEWALT Camaro.
“Harri has great potential, and we’re eager to explore how he might fit into the future of Team 18.”
Anton De Pasquale is already signed to replace Winterbottom as the driver of the team’s #18 entry next season.
The team is understood to have recruited Lee Holdsworth to co-drive with Reynolds, with its plans for a second co-driver unclear.