Three passing police officers spotted the tourist bus in Smiths Creek, Portsmith about 7pm on Sunday night.

Two officers used torches and their vehicle's headlights to watch out for crocs while a third officer entered the water, eventually dragging out the sole occupant through the bus windscreen.

The driver, 36, was taken to hospital with non-life threatening injuries.

Senior Sergeant Duane Amos said the officers had probably saved the driver's life, after his vehicle began taking on water and sinking into thick mud.

"The rapid response by the officers, seeing the bus sinking and flooding the compartment area, has averted a tragedy on the quickly submerging bus," he said.

Australian Associated Press