The federal government is taking allegations of corruption and water theft in the Murray-Darling Basin "abundantly seriously", Deputy Prime Minister Barnaby Joyce has told parliament.
Mr Joyce was asked by Labor frontbencher Tony Burke on Tuesday why a series of investigations could not compel witnesses, take evidence on oath, seize documents or protect whistleblowers.
"Why won't the deputy prime minister commit to a national judicial inquiry through COAG to ensure the Murray-Darling Basin plan is not undermined?" Mr Burke asked.
Mr Joyce, who is also the minister in charge of water issues, said a lot of work was going into the investigation into what were still only "allegations".
The NSW government-appointed investigator Ken Matthews had experienced support staff.
As well, the state's top water bureaucrat Gavin Hanlon had referred himself to the NSW Independent Commission Against Corruption.
The auditor-general was looking at the issue and an independent review had been commissioned by the Murray-Darling Basin Authority.
"We are taking this thing abundantly seriously and we are pursuing this issue through to make sure that if someone has thieved something, that they will be found out," Mr Joyce said.
Labor plans to seek parliament's approval this week for a judicial inquiry.
It has the support of the Greens, the Nick Xenophon Team and the Australian Conservatives.