The Productivity Commission has warned that billions of dollars in water infrastructure is being wasted due to lack of cost-benefit analysis, misdirected subsidies and a reluctance to properly plan dams and water distribution works.

The government, under pressure from the Nationals, has committed to $4 billion in water infrastructure since coming to office, about half of which has already been spent on dams and irrigation infrastructure. That's despite the Productivity Commission repeatedly warning that government spending on irrigation infrastructure -- particularly when done in the name of conserving water -- is highly inefficient. Back in 2010, the PC warned