Despite plans for the environment to be better off as a result of the upgrades - which will reduce water loss in the farming sector - officials concede that rises in salinity will be among the minor environmental negatives attached to the project.

NVIRP, the authority delivering the project, confirmed the upgrades would reduce the amount of water that enters the Murray as ''outfalls'' - excess water not diverted by farmers.

The reduced outfalls will mean that less of a dilution effect occurs in the river, raising salinity.

One-third of water saved in the upgrades has been promised to the environment, and project spokeswoman Merrill Boyd said that boost in environmental water would overshadow any other environmental concerns.