Northern NSW storm conditions ease

The stormy conditions in northern NSW are easing as ex-tropical cyclone Marcia moves south from Queensland and weakens.

State Emergency Service's Jenny Slater says there have been 20 jobs since 6pm on Saturday, following a torrent of more than 700 calls since Friday.

"It has eased significantly overnight," the duty operations officer told AAP.

"It is because the rainfall that was predicted for that area did back off and ease off overnight."

Flood warnings remain in place from Coffs Harbour upwards, while gale force winds are predicted to buffet the Byron coast, the Bureau of Meteorology says.