Mallee Nationals MP Anne Webster says federal Water Minister Tanya Plibersek is in a "ruthless push" to pursue water buybacks.
Dr Webster said the minister was prepared to disregard farmers, whose livelihoods depended on irrigation, as well as the Victorian and NSW governments, in her bid to deliver the 450 gigalitres of environmental upwater.
The 450GL is to be recovered through reduction in losses through irrigation, commercial use and public water supply infrastructure.
Dr Webster said reducing fruit and vegetable production through buybacks would hurt families at the supermarket checkout.
"This demonstrates yet again Labor is focused on political pet topics rather than the cost of living crisis," Dr Webster said.
"Past buybacks left irrigation districts as a patchwork of properties of those with water abundant and those without arid.
"People and towns in the Basin that rely on water being delivered to our highly valuable horticulture industry will miss out."
She said the Mildura-Swan Hill region was expected to have a Gross Value of Production in horticulture of $2.2 billion per annum by 2029-30 but buybacks would seriously compromise that.
Dr Webster said the former government implemented an economic neutrality test, first developed by former Labor Water Minister Tony Burke, to ensure that buybacks would only occur, if they had negative social or economic consequences.
Dr Webster said the Federal Labor Government needed to work with the States, as the former government had done, to deliver the plan without compromising communities' sustainability along the Basin.
"The minister has had 16 months in government to work cooperatively with the states to agree to extensions of time to complete planned Sustainable Diversion measures," Dr Webster said.
"Now the elephant in the room has been addressed, namely the government's admission that the Murray Darling Basin Plan's June 2024 deadline won't be met, the minister is looking to the Greens to help Labor run roughshod over farmers, states and farming communities with no heed for the socioeconomic neutrality test."
The Greens had already urged the government to restart buybacks and guarantee the delivery of the 450 gigalitres, despite opposition from peak farming groups.
Labor would bring forward legislation before the end of the year to prevent a breach of the Water Act.
"To formally legislate delivering the 450GL with the Greens' support, Labor only needs two more votes from the Senate crossbench," Dr Webster said.
In March, Ms Plibersek announced tenders for the the federal purchase of 41,100 megalitres of surface water from six Murray Darling River valleys.
She said the government was currently evaluating bids, that had come in, and was shortly expected to make offers.
"I'm talking with states and territories right now, but it is very clear that to achieve the plan in full we will have to deliver on those infrastructure projects that the states have indicated,"
She said NSW water resource plans, due in 2019, were only just being accredited.
The Minister declined to say how much water would need to be purchased.
"These are all things that we are discussing with the states and territories right now," she said.
"I'm not going to pre-empt those conversations."
