Police probe fatal Qld jet ski crash

A young boy is seriously injured after a jet ski crash that also injured his father and killed his older brother near Mount Isa.

The six-year-old has been flown to Townsville for specialist care after the jet ski he and his father were riding hit and killed his nine-year-old brother at Lake Moondarra on Saturday.

Police divers found the older boy's body early on Sunday.

The jet ski struck the boy and then hit the banks of the lake, throwing the father and younger child onto the shore. Both were injured but the father has since been released from hospital.

Police Superintendent Kev Guteridge says the lake is popular with Mount Isa families, and the boy's death has rocked the community.

"A young child was swimming in shallow water and was struck by the jet ski. The jet ski then collided with the bank, the riders ... were thrown onto the bank where they sustained their injuries," he told ABC radio.

"It's an area I'm very, very certain the family were very,very familiar with and just in a split second, one error of judgement, something just goes wrong."