A RED alert warning for blue-green algae along the Murray River between Wentworth and Lock 9, including Fort Courage, has been issued by WaterNSW.

The alert was issued on Wednesday and adds to the current red alert warning between Red Cliffs and Wentworth declared this month.

WaterNSW issued the alert after undertaking tests with local water authorities.

Levels of blue-green algae continue to f...