The clean-up operation has got under way across eastern Australia after the passage of Tropical Cyclone Debbie. Despite drier conditions over the weekend, flood waters remained high, but they are now starting to recede.

Residents and business owners have been returning to thick mud, piles of debris and ruined property. While the worst of the weather is over, with Cyclone Debbie moving out to sea on Saturday, the daunting task facing those affected is just beginning.

The flood-ravaged people of northern New South Wales and southeastern Queensland have also been faced with raw sewage, rats and snakes.

Military and emergency personnel continued to work to restore essential services such as water and electricity in affected towns, where hundreds of homes have been deemed uninhabitable.

The Insurance Council of Australia has estimated the damage bill could reach Aus$1bn ($770m), as people braved mud-caked streets to begin clearing out homes and shops, with mountains of ruined possessions piled on pavements.

New South Wales State Emergency Services Deputy Commissioner Mark Morrow said it would be a long haul for towns such as Lismore and Murwillumbah that were inundated by floods.

"The mud, combination of chemicals, raw sewage, paint which gets into everything. Two to three metres above floor level. Nothing escaped this. It was a very, very big flood," he said.

Prime Minister Malcolm Turnbull said seeing the damage up close was heartbreaking, as he toured Lismore.

"Seeing it first-hand and the impact, treasured possessions, all of a life's work, all of the assets of a business flung out on to the pavement - that is gut-wrenching stuff," he said.

The cyclone dumped more than a metre of rain on parts of Queensland and the huge volume of water is still slowly spilling down river systems, with Rockhampton next in the firing line.

As floodwaters creep closer to the city, those waters are expected to peak at around nine metres on Wednesday morning.

The floods may not be as bad as initially feared but Queensland Premier Annastacia Palaszczuk said: "We do want to stress to the people of Rockhampton that you still need to make your flood preparations.

"We are not out of the woods yet. There is still a long way to go," she added, stressing that 300 schools in the state had been damaged and needed repairs.

Thankfully, the weather for Queensland and New South Wales looks largely dry for the rest of this week as the remnants of Debbie head towards New Zealand. However, the impact of the storm will be felt for many months to come.