Such a move, part of the Sustainable Diversion Limits projects, would "further reduce water flows in the lower Darling River and destroy fish breeding grounds in the Darling River", Labor said, adding it had "committed to abandon this plan to prevent further ecological destruction".
Critics have blamed state and federal governments for "throwing out the window" policies which protected the river.
In a tweet, Mr Buckingham said he was "involuntarily retching from the smell".
Independent MP Jeremy Buckingham posted the footage of the incident to Twitter earlier today. "I felt so sick that I panicked and jumped in the river to escape it - as bad as it is!" he explained.
He said the Murray-Darling Basin Authority could also appear to answer some questions too.
In a video that has been viewed almost 4 million times, Menindee resident Dick Arnold and rancher Rob McBride say the fish kills are "a manmade disaster".
"It has everything to do with the total mismanagement and corruption of the water system", Mr McBride told AAP on Wednesday.
Up to a million fish died in the Darling River this week, with many carcasses sinking to the bottom of the river while others rot along the riverbanks.
Some experts to fear whole populations of local native fish have been wiped out. "But the river droughts are happening more often and they're more intense as a result of the irrigation industry in the Darling diverting water from the river over the last 10 to 20 years".
Millions of fish are thought to have died after a blue-green algae event in recent days.
The Menindee Lakes, which are about four times the size of Sydney Harbour, were drained twice in four years and are sitting at between 2.6 per cent and 4 per cent capacity, he said.
"The huge extraction of water for big irrigators is literally choking the life out of the system downriver and leaving stagnant, blue-green algae infested dregs for everyone else", he said.
Arnold says members of the government "have to be bloody disgusted with yourself, politicians and cotton grower manipulators".
The immediate cause of the mass fish kill is believed to be a sudden drop in temperature that killed algal blooms in the water, depleting it of oxygen and causing fish to die.
Mr McBride said: "This is nothing to do with drought, this is a man-made disaster". The fish kill in the Darling River that we have witnessed, that Dick and Rob have put on social media and is going viral is an absolute catastrophe.
A South Australian royal commission in 2018 investigated allegations of water theft from the Murray-Darling basin by rogue irrigators with a report due in February.