Two farmers have blamed the government for a natural disaster causing hundreds of thousands of dead fish to wash up along the banks of the Darling River.

Rob McBride from Tolarno Station in central western New South Wales and fellow farmer Dick Arnold posted a video to social media of them holding up two Murray Cod they say could be a century old after they were killed in the disaster.

'This is nothing to do with drought. This is a man-made disaster brought to you by the NSW Government, the Federal Government, and the Murray Darling Basin Authority. It is the result of draining the Menindee lakes twice in four years and killing the system,' Mr McBride said.

Two farmers from central western New South Wales (pictured) have said the government is to blame for a natural disaster causing millions of dead fish to wash up along the banks of the Darling River

The Murray Darling Basin Authority was established to manage the river system under a multi-billion-dollar plan agreed upon by the states the massive river system stretches across.

It has come under heavy criticism for allegedly allowing farms upstream to monopolise water resources.

An international report published in 2017 claimed the authority's 'subsidy programs' to save water have been 'ineffective, poorly conceived' and have 'primarily benefited private individuals,' according to The Guardian.

The Department of Primary Industries has sent staff to the Menindee region to investigate the phenomenon which is thought to have occured due to an algal bloom which then died off and affected the amount of oxygen in the water.

Fisheries Manager Iain Ellis told reporters this is the first time he's seen two such sad and shocking fish kills so close together

Hundreds of thousands of fish (pictured) have been killed along a 40-kilometre stretch of the Darling River

Native species, including Bony Bream, Murray Cod and Perch are thought to have been just some of the breeds affected, according to ABC News.

The same section of riverbed in the freshwater lakes of Menindee, near Broken Hill in the far west of New South Wales, suffered a similar natural catastrophe just before Christmas when an estimated 10,000 fish died.

Department of Primary Industries Fisheries Manager Iain Ellis told reporters this is the first time he's seen two such sad and shocking fish kills so close together.

'I've never seen two fish kills of this scale so close together in terms of time, especially in the same stretch of river,' he said

'In both cases it's when the algal bloom has been disrupted.'

Native species, including Bony Bream (pictured), Murray Cod and Perch are thought to have been just some of the breeds affected

WHAT IS ALGAL BLOOM? The mass kill occurred because an algal bloom had been disrupted due to a shift in water temperature When an algal bloom is disrupted it can cause the algae to die When the plants die, they decay and draw oxygen from the water Lower levels of oxygen in natural waters can kill marine life The mass kill can occur from purely natural causes Advertisement

'The first time due to a storm, and in this case, by the cold front that went through,' he explained.

Local residents have been taking to social media to share the shocking images of the lifeless fish.

One man took to his Facebook account to attribute the incident to the lack of water in the lakes.

'Fish still dying in the Darling at Menindee this morning 10's of thousands yesterday there be 100's of thousands if not in the Millions today,' he wrote.

'Menindee lakes were almost full less than two years ago now there's no water left.'

However, a spokesman from the Department of the Environment and Energy denied the fish kill was due to the mismanagement of water.

'A fish kill of this nature is always very distressing but the causes are directly related to the current drought and cease-to-flow conditions,' the spokesperson said.

Local residents have been taking to social media to share the shocking images of the lifeless fish (pictured)