A massive pile-up involving almost half the Supercars field has caused millions of dollars worth of damage and suspended racing at Symmons Plains.

A dozen drivers – including Garth Tander, James Courtney, Scott Pye and Rick Kelly – were caught up in the mayhem.

Will Davison, badly winded, has been taken to hospital suffering lower back pain after the impact which has been described as a 9G-force impact.

Spray from the wet Tasmanian track impeded drivers as they headed down the straight in front of the crowd at over 200 kilometres an hour.

The conditions made it difficult to ascertain the origins of the crash, but contact on Tander appeared to set off a chain reaction.

The Wilson Security Racing driver span out, possibly after a shunt from Cam Waters, and brought most of the field with him.

“Ive got no idea (what happened) … I’m not blaming anyone at this stage,” Tander said.

“Someone hit me in the rear and I went sideways. Sideways there is not good because the whole field is coming at you.”

Of the impacted 12 cars, 10 are Commodores and two are Altimas.

Team owners and drivers appeared distraught from the garage.

“There are five million dollars of motorcars sitting there,” ex-driver Mark Skaife said on the Fox Sports broadcast.

“This is like a wrecking yard. Staggering damage.”

Courtney said he was good “but the cars aren’t”.

“I was stopped and a car behind me, I think it was Taz (Douglas), didn’t see the accident and hit me.”

The cars of Tim Slade, Nick Percat, Tim Blanchard, James Moffat, Alex Rullo, Will Davison and Douglas also sustained major damage.

It appears that the majority of the impacted dozen won’t be able to compete in the rest of the Symmons Plains meet.

Simona De Silvestro was also involved but managed to wriggle free to pit lane.

Shane van Gisbergen was leading the race when it was red flagged, ahead of Scott McLaughlin and Jamie Whincup.

In the mayhem, McLaughlin opted to head into the pits – a move that is likely to send him to the back of the grid for the restart.