The Australian Senate has adjourned without resolution following a lengthy debate on a crucial bill related to the Murray-Darling Basin plan.
The upper house on Tuesday adjourned without passing a bill allowing for changes to be made to the amount of water that can be sustainably taken from the basin.
AAP reports the legislation must pass the chamber this week if Environment Minister Tony Burke is to present a final basin plan to parliament for consideration by the end of the year.
After a protracted debate, a coalition spokesman said the bill signalled that parties were coming close to the end of a very long, tortuous and drawn out process in water reform.
"For more than 120 years, particularly the Murray Darling Basin states have argued and squabbled and bickered over water reform," Senator Simon Birmingham told the chamber.
He welcomed government co-operation with the opposition on the legislation.
Labor Senator Doug Cameron said the bill "might not be everyone's nirvana, but it's a massive step forward".
AAP reports the Greens moved a flurry of last-minute amendments, but all were defeated.
Under amendments made in the lower house, the environment minister of the day has the final say on any adjustment levels, not the Murray-Darling Basin Authority.
Barnaby Joyce said it was the 2.1 million basin residents who stood to lose considerably if any more of their water was diverted downstream.
"We have to be extremely cautious of how this process works," said Opposition water spokesman Senator Barnaby Joyce.
AAP reports that though agreeing with the bill, the opposition moved an amendment to ensure any adjustments must operate on a "no-detriment" basis - meaning they would not have adverse social, economic or environmental outcomes.
