If Queensland wanted to withdraw its support of the Commonwealth managing the state's Murray-Darling Basin catchments, as Minister Andrew Cripps threatened yesterday, it would be a fairly straightforward political act. But the decision could have constitutional consequences that would test the High Court, legal experts tell Crikey.

State governments have until July 9 to voice their concerns to the federal Water Minister about the current Murray-Darling Basin draft plan. With the final week of negotiations under way, Cripps told ABC Radio that his state would consider ending its referral of power of basin catchments to the Commonwealth. Victoria, South Australia and New South Wales also signed over the same referral of power in 2008.