Labor has said it will push ahead with plans to set up an inquiry into the contentious taxpayer-funded water buybacks, after a request for documents was not met on Tuesday.

Key points: Shadow Water Minister Tony Burke says Agriculture Department's failure to provide details shows coercive powers are required

Shadow Water Minister Tony Burke says Agriculture Department's failure to provide details shows coercive powers are required Agriculture Minister David Littleproud has called for a review of all water buybacks under the Murray-Darling Basin plan since 2008

Agriculture Minister David Littleproud has called for a review of all water buybacks under the Murray-Darling Basin plan since 2008 Mr Burke said Labor welcomes that review but it would not have the power to compel witnesses to testify

Shadow Water Minister Tony Burke said the Agriculture Department's failure to provide details by close of business showed coercive powers are required to investigate the deal.

In 2017, the Government spent $80 million to acquire the water rights to two properties in Queensland.

The money was paid to Eastern Australia Agriculture (EAA), which is controlled by a company based in the Cayman Islands — a well-known tax haven.

Barnaby Joyce, who was the water minister at the time and who signed off on the deal, maintains he did nothing wrong.

Labor has pledged to launch a judicial inquiry into the controversial water buyback deals if it wins government.

Mr Burke denied the investigation is politically motivated, despite suggesting it won't extend to Labor's time in office.

"On this particular issue, the questions that are being asked on this — and [that] the Government is refusing to shed a light on — have not been questions asked of any other minister," he said.

Mr Burke was the minister for the environment and water from 2010 to 2013.

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Calls for review of all buybacks since 2008

Agriculture Minister David Littleproud has written to the Auditor-General calling for a review of all water buybacks under the Murray Darling Basin Plan since 2008.

The review would look at all deals struck under Labor and Coalition governments during that time.

Mr Burke said Labor welcomes that review but it would not have the power to compel witnesses to testify.

It is still not known who the investors within the Cayman Islands company are, or who ultimately benefitted from the 2017 buybacks.

"You set up companies in the Cayman Islands — one of the reasons is for the secrecy that's attached to it and that means only an inquiry with coercive powers can get to the bottom of who was actually involved," Mr Burke said.

Mr Joyce said the Opposition also made purchases from EAA and demands the same questions be put to them.

"The trouble with the Labor Party is they were first. So whatever they did, they did first. And we were following their precedent because they sold it to them," he said.

Under the former Labor government and in the early years of the Abbott prime ministership, all buybacks were under open tender.

Owners would register the price they would be prepared to sell for and the department would decide which offer provided best value for money.

However, there were concerns from some communities that this led to job losses and in 2015 Mr Joyce changed that process.

Since then, the Government has only bought water from willing sellers through direct negotiation with entitlement holders.