Four people have been critically injured in an accident at a theme park on Australia's east coast.

Queensland state police say all four were injured Tuesday on a ride at Dreamworld, a popular theme park on Queensland's Gold Coast.

Police spokesman Kieran Self says police do not yet have information on how the injuries occurred or what ride was involved.

Aerial footage of the park showed paramedics at Dreamworld's Thunder River Rapids ride, which features circular rafts that carry riders along a fast-moving, man-made river.

The Queensland Ambulance Service said paramedics were on the scene.

Dreamworld did not immediately respond to requests for comment.