Flood waters have swamped vast swathes of northwest Queensland, killing cattle in their thousands and leaving entire herds isolated and facing possible starvation.

Grazier Jamie Zammit at Wyreema Downs, south of Julia Creek, says it's too boggy to inspect his 30,000-acre station but in the paddocks he can get to he's found stock losses at 50 per cent.

"It's pretty shitful. I can't see anything but rain and dead animals," he told AAP.

"At the end of the day it's pretty much a disaster, everyone battled through the drought then got three years of rain in 10 days."

"This country can't handle rain like that, there are creeks where there were never creeks and we've never had rain like this in a 100 years of records."

In Winton Shire, where 700mm of rain fell in 10 days, mayor Gavin Baskett said some cattle were being swept away and drowning, while others were dying of exhaustion or starving in the knee-high mud.

"The cattle were (in poor condition) because there was no feed in the paddocks and now we've had 11 days of constant and heavy rain the cattle are having a battle moving around," he told AAP.

"It's becoming quicksand out there. It's a pretty sad situation."

Rural Aid chief executive Charles Alder said hundreds of farmers were facing a dire situation, with up to 300,000 head of cattle affected.

"The expectation is a fairly substantial number of stock has been lost in the floods, washed away or drowned. We know of instances where thousands of cattle have gone missing," he told AAP.

"If we were to estimate the cattle had a value of a thousand dollars per head we're talking $50 to $100 million worth of stock losses."

He said getting help to flooded communities was very difficult, given how widespread the flooding was.

Forty trucks of fodder were already heading north to affected communities, and the group is hoping to work with the federal government and shires to fly hay into flooded communities, Mr Alder said.

Assistant Minister for Home Affairs Linda Reynolds said recovery grants of up to $25,000 would be available for primary producers in seven local government areas.

"Gut-wrenching information has come through about stock losses of 25 to 50 per cent of entire herds of cattle and groups of 300 to 400 cattle clustered along fence lines as well as dead animals in flood water flowing through and around towns," she said.

There are now 21 local council areas in Queensland receiving a range of assistance.

Australian Associated Press