Raging, snake-infested floodwaters are frightening residents in the sodden city of Rockhampton as they evacuate their homes ahead of the Fitzroy River's peak.

More than 20 cities and towns are waterlogged around Queensland as the state remains in the grip of a flood crisis.

The river in Rockhampton, described as a chocolatey, yellow colour and choking with debris, is predicted to peak at 9.4 metres tomorrow.

Residents say they are having to deal with raw sewage, swarms of mosquitoes and power blackouts.

Resident John Peacock had to flee the floodwaters with just one change of clothes.

He says it is heart-breaking knowing everything he owns is being ruined.

"It's really, really dirty. I don't know why, but it's picked up a lot of mud at the moment," he said.

"Even around home the water is so dirty you thought you could walk in it, but the water is not just clear - it is a chocolatey, yellowy colour. It looks so scary at the moment."

He says the floodwaters are too frightening to wade through.

"It's a raging torrent. It's raging, it's roaring down and it's very, very wide," he said.

"There's heaps of snakes at the moment in that water and I just knew if I went back to have a look and see if I could salvage anything that I was taking the risk of getting bitten."

Mr Peacock's home is among 500 being vacated because of the floodwaters, while about 90 locals are staying at an evacuation centre.

Jenny Smith from the Red Cross says more may come tonight.

"We've had 88 people stay with us overnight - mostly local people from various parts of flood-affected Rockhampton, but some of those are also travellers who have been stranded here," she said.

"We've just been going through the normal motions of the usual day. We think routine is a pretty important part of an evacuation centre."

Mayor Brad Carter says the flood crisis in the city and outlying areas is set to continue for weeks.

"I was absolutely amazed when I saw the extent of the water coming across the Pink Lily Lagoon area through the Yeppoon flood plains, flowing across both the Capricorn Highway and the Bruce Highway," he said.

Supplies flown in

The Fitzroy River is expected to peak about 9.4 metres sometime tomorrow, inundating hundreds of homes and affecting thousands of properties.

The floodwaters have nowhere to go and hydrologist Peter Baddiley says they are likely to stay around that level for several days.

For the second day in a row, a RAAF cargo plane loaded with goods took off from Amberley, south-west of Brisbane, and landed in Mackay to Rockhampton's north.

Barges filled with food have been ferrying supplies from Gladstone and helicopter drops are also being made, while other supplies are being trucked in through the one highway in and out of the city.

New Zealand is sending a small emergency management team to help authorities deal with the disaster.

Rockhampton pharmacist Brendon Reck has been able to stock the shelves with medical supplies but some of his staff are stuck.

"We have one staff member who has evacuated her property and is living at the showgrounds with her horses and cattle," he said.

He says stranded travellers can still get prescriptions if they do not have their medication.

Overwhelming cost

The floodwaters are receding in some towns and regional areas, revealing the overwhelming cost to residents and farmers alike.

Insurance assessors have been on the ground for the first time in some places, including Bundaberg.

About 1,800 claims have been lodged already for flood damage.

The cost to the coal industry is estimated at $1 billion in lost production.

Much of the state's crops are waterlogged and ruined, with AgForce saying the cost to agriculture is also $1 billion.

In the state's southern inland, locals from the large cotton-growing community of St George are preparing for its second massive flood in a year.

The town's Balonne River may climb higher than 14 metres.

A temporary medical centre is open and residents have been building makeshift moats to protect their homes.

Emergency Management Queensland says there is no relief in sight to many flood-affected communities.