Just after 3am, police and emergency services were called to Milne Road after reports that a motorcycle rider and his male passenger had crashed.

The rider, a 38-year-old Redwood Park man died at the scene.

His passenger, a 45-year-old Clearview man was rushed to hospital for treatment.

His injuries are serious, but are not believed to be life-threatening.

Major Crash investigators attended the scene to examine the circumstances of the collision, but roads have since reopened.

The man’s death is the 51st life lost on South Australian roads this year, compared with 66 at this time last year.

Meantime, five teenagers have been killed in a horror road smash southwest of Sydney.

The driver, an 18-year-old man, survived the single-vehicle crash and was taken to hospital with injuries not considered life-threatening.

Police say his Nissan ute lost control and struck a tree at the intersection of Orange Road and East Parade near the Macarthur Region village of Buxton about 8pm on Tuesday.

Authorities say three female and two male passengers, still to be formally identified but all believed to be of a similar age, died at the scene.

Camden police chief Superintendent Paul Fuller said the accident scene was the worst he’d seen in 38 years in the force.

“Unfortunately some of the first responders would know these kids,” he told reporters.

“Look some of these kids are 14, 15.

“Can I just say to parents, know where your kids are.”

Supt Fuller said the ripple effect of the tragedy would be felt heavily by the small local community.

Police said the driver had been taken to Sydney’s Liverpool Hospital where he had undergone mandatory blood and urine tests. He had not been placed under arrest.

Investigators are appealing for anyone with dashcam footage or information about the incident to contact them.

-with AAP