A 45-year-old man has been killed in a quad bike crash on a private property near Port Lincoln, the second death involving quad bikes in South Australia in two days.

Police said the alarm was raised just before 6pm on Sunday following a crash involving a quad bike at a private property at Whites Flat, about 20 kilometres north of Port Lincoln.

Police said the man was pronounced dead at the scene.

In a separate incident in the Adelaide Hills on Friday night, police said a 92-year-old quad bike rider was taken to hospital with life-threatening injuries and died on Saturday morning.

Last week, a 50-year-old Hackham man died in a separate quad bike accident on private property on the state’s Yorke Peninsula. 

Crews were called to a property near the Spencer Highway at Port Broughton just after 1:30am last Saturday following reports two quad bikes had crashed into a fence in a paddock.

A 39-year-old Pennington man sustained serious injuries and was airlifted to the Royal Adelaide Hospital for treatment.