Using desalinated water to boost allocations to River Murray irrigators in South Australia would be too costly, a study has found.

The cost-benefit analysis was commissioned by the state government to consider producing more water at Adelaide’s new desalination plant to boost supplies to irrigators who have started the new financial year with an allocation of just over a third of their full entitlements.

But Water Minister Ian Hunter says the results show that providing desalinated water wouldn’t be economically viable and reflect the fact that the desal plant was built to provide water security to Adelaide during times of drought.