Days of fish kills expected after ex-tropical cyclone

Habitat charity OzFish says thousands of fish have been washing up dead or dying in northern NSW. (HANDOUT/OZFISH)

Members of the public are being urged to help track the extent of a fish kill in a region hit hard by ex-tropical cyclone Alfred.

Thousands of fish have been washing up dead or gasping on the banks of the Richmond River at Ballina in northern NSW, according to habitat charity OzFish.