A carer has been charged with the manslaughter of two elderly people killed in a single-vehicle crash in Queensland, with police now alleging the crash was intentional.

The 61-year-old man was behind the wheel of a Suzuki Kizashi which crashed into a tree at the intersection of Callemonda Road and Mary Valley Road at Brooloo, about 60km northwest of Nambour, just before 2pm on Monday.

“There was extensive damage to the car. It drove head-on into a tree,” police said.

Know the news with the 7NEWS app: Download today

An 83-year-old man from Kandanga, who was in the front passenger seat, and an 85-year-old woman from Gympie, seated in the back, died at the scene.

“The two victims were related and their relationship with the driver was in a professional manner,” Acting Superintendent Brad Inskip said.

“He was employed in a caring role.”

The driver, from Valdora, suffered serious injuries and was airlifted to Sunshine Coast University Hospital, where he remains under police guard.

On Tuesday, detectives charged him with two counts of manslaughter following what was initially believed to be a tragic accident.

“We now believe that crash was not an accident but a deliberate act,” Acting Superintendent Brad Inskip said.

The accused is expected to face a bedside hearing at Gympie Magistrates Court later on Tuesday.

Police are urging anyone with further information to come forward and investigations are continuing.