The massive fish kills at Menindee and other environmental strains have revealed huge gaps in the ecological data collected in the Murray-Darling Basin, according to Tony Burke, federal Labor's water spokesman.

Mr Burke, who earlier this week visited Menindee, said the deaths of up to a million fish in the lower Darling this month had made it "an absolute priority" to get better information about the state of the basin's ecosystems.

Too little information has been collected about the ecology of the Murray-Darling Basin, Labor says. Credit:Dean Sewell

"We're dealing with something beyond the problems we've seen before," Mr Burke told the Herald.

After speaking with agencies, Mr Burke said it was clear they were good at monitoring water volumes but lacked the funds to track sufficiently the health of the ecology of the basin - including where things were improving.