Wading through flooded areas can be dangerous anywhere in the world, but in Australia the waters may contain snakes, crocodiles and sharks as well as rubbish and sewage.

One of the striking images showing the impact of category four Cyclone Debbie which smashed through northeast Australia this week was a paramedic's photo of a large bull shark that washed up on a road near the town of Ayr.

And sharks are not the only unusual sightings in floodwaters in Australia's tropical north. Queensland state authorities warned that crocodiles and snakes could also be lurking around after Debbie hit.

"Flooded waterways increase the possibilities of crocodiles and other animals, such as snakes turning up in unexpected places," the state's environment and heritage protection department said.

"In most circumstances, crocodiles will be moving through, trying to get out of fast-flowing creeks and waterways to the quieter areas they prefer.

"Snakes are good swimmers and they too may turn up in unexpected places and may even find their way into people's properties."

Paramedic Lisa Smith, who photographed the bull shark, said she was stunned to find it lying near the Burdekin River.

"At first I thought it was a dolphin, but then I thought 'nah, there wouldn't be any dolphins around here,'" Smith told Brisbane's Courier Mail.

"I thought there were just crocs in that river. This should definitely teach people to never walk in floodwaters as you never know what's in them."

Snake catcher Anthony Bailey, from Yeppoon in central Queensland, offered on Facebook to remove the reptiles for free after the storm, and received a flood of responses.

"Already had a brown (snake) at our back door. Good on you guys for offering free assistance during this time," one person replied.

Bailey said snakes were fond of slithering indoors in wet conditions.

"They don't like sitting out in the rain, they come into houses or trees to escape the water and possibly looking for some warmth," he told the Rockhampton Morning Bulletin.

Australia is home to 20 of the world's 25 most venomous snakes, including the entire top 10.

Brown snakes, among the most venomous, are common in eastern Australia and can be as much as two metres (six feet) long when fully grown. Their bite can be fatal to humans.

Source: AFP