A Queensland grazier and environmentalists have sounded a dire warning about the future of three rivers that feed into Lake Eyre in outback South Australia.

A conference in Adelaide has been warned the spectacle of a brimming lake could become a memory if the Queensland Government proceeds with a plan to open up the rivers to irrigation and mining uses.

The Government wants to remove wild rivers legislation that covers the three rivers.

Queensland grazier Angus Emmott warned South Australians should be concerned.

"The monsoonal influence across Queensland is what provides most of the water to Lake Eyre," he said.

"If we reduce that over time, there'll be less water going into the lake less often and the ecological processes won't work as well, but the eco-tourism benefits to South Australia will be strongly affected as well."

A director of the Pew Environment Group Barry Traill said a new approach to managing the river system could wreck one of the greatest wildlife spectacles on the planet.

"Up to now local graziers, Aboriginal people, conservationists have been successful in saying 'No, these rivers are natural, they're very, very important for people, for wildlife, they need to be protected'. So it's of great concern that the Queensland Government is considering removing that protection," he said.

"I hope that the Queensland Government will listen. This is one the great iconic river systems of Australia, one of the most beautiful parts of the outback and it should be protected permanently."

Queensland rural lobby group AgForce CEO, Charles Burke, said even if the wild river legislation were scrapped, there was adequate protection for the system.

"I don't believe it will have any bearing on the river system because there is already regulation and legislation through other acts that impose certain requirements on what water can be used and how it is extracted," he said.

"This was always just another layer of complication and compliance which farmers just simply didn't need."

Lake Eyre is usually a dry saltpan and only sees water after heavy rains in eastern Australia.