Two sharks seen off NSW north coast following fatal attack

Two large sharks have been spotted of the northern NSW coast where a surfer was fatally attacked, forcing authorities to reassess beaches.

A four-metre shark and a three-metre shark were seen in waters near Ballina late yesterday afternoon.

On Monday morning Japanese man Tadashi Nakahara, 41, was bitten by a three-metre great white while surfing off the coast of Ballina, in the fourth fatal shark attack in five months.

Rescuers took Mr Nakahara to shore and performed CPR but he died on the beach.

"The situation will be reassessed (on Thursday) with public safety being the paramount consideration," police said.

Experts have said warm water and runoff from rainfall is attracting small fish to the area, which in turn attract sharks.