Manly beach has been closed to swimmers after a tiger shark was spotted just before 1pm on Monday.

A Manly Council spokesman said the shark was seen by a surfer about 12.45pm.

The surfer was not able to see how big the shark was but was able to identify it by its fin.

He then made his way to shore and reported the shark to lifeguards who then closed the beach.

They are currently patrolling the area in a jet ski to see if the shark is still present.

The beach will remain closed as a precaution and is expected to reopen on Tuesday morning.

It follows a series of shark sightings along the northern NSW coast from May 4 to May 6.

Shark reporting service Dorsal noted six sightings over three days from Yamba to Kingscliff, just south of the Queensland border.

However, all were of tagged bull sharks.

But on Saturday afternoon, Surf Life Saving NSW reported a shark sighting just off North Curl Curl.

And on Saturday morning a shark was spotted on the Central Coast, about 20m from shore.