A Porsche driver has been arrested after allegedly causing a fatal crash and then embarking on a string of carjackings and a shooting on the Sunshine Coast in Queensland.

Police said the incident began with a major crash on the Bruce Highway on Monday at Palmview.

They believe a red Porsche Macan crashed around midday and caused a fatal collision that involved multiple vehicles.

One woman, who was in a different vehicle, died as a result of the crash and an injured man was taken to hospital.

After the pile-up, police said the driver got out of the Porsche armed with a gun.

He allegedly approached a white SsangYong Rexton and shot the male driver in the arm, police said.

Investigators do not believe the two men knew each other.

The man with the firearm then allegedly stole the Rexton, fled the crash site and later hijacked another car before being arrested.

The first stolen car was found crashed in Landsborough and police allege the man then stole a grey Mazda 3.

Queensland Police Chief Inspector Jason Overland said a young male doing driver training with his mum and dad were inside that car when it was “hijacked”.

“I’ve given up trying to work out why,” Overland told reporters at Caloundra on Monday afternoon.

“It’s just a tragedy and we’re doing all we can to address what’s left.”

He asked drivers to be patient as police were processing three separate crime scenes.

Anyone with information about what happened has been urged to contact investigators.

-with AAP