Concern continues to mount in Australia at the growing internet craze of "planking" with four people arrested in a Queensland crackdown and new warnings about its dangers.

The warnings followed the death at the weekend of Acton Beale, 20, who fell seven stories when he planked on the balcony of his Brisbane apartment.

The craze of lying face down in unusual public places and posting images on the internet has soared in popularity since the tragedy.

Police feared another man had fallen victim when 20-year-old Simon Hallam was taken to hospital in the northern New South Wales city of Tamworth suffering serious head injuries after falling from a car on Monday night.

Early reports said Hallam, who was yesterday in an induced coma at Tamworth Base Hospital, had been planking at the time of the accident, but police said yesterday that witnesses and mobile phone footage showed he had been standing on the boot of the moving car when he fell.

The 19-year-old alleged driver has been bailed to appear in court on June 16 charged with dangerous driving causing grievous bodily harm, and negligent driving.

In Queensland police have charged three men for riding on the roof of a moving car in Toowoomba, and the female driver has been charged with dangerously operating a motor vehicle.

"We would question their level of intelligence and due regard to self-preservation," acting Inspector Jim Fenton told the Toowoomba Chronicle.