Wollongong City Council lifeguards were alerted to four hammerhead sharks, each about two metres long, lurking off the beach shortly before 1.30pm.

Bendigo Bank Aerial Patrol general manager Harry Mitchell said the sharks were ‘‘in and just outside the surf zone’’.

‘‘We had Port Kembla lifeguards ride out there on a jet ski to help push the shark that was in the surf zone further out to sea,’’ Mr Mitchell said.

The area was deemed safe following a second aerial patrol 40 minutes and the beach reopened about 3.45pm.

Mr Mitchell said multiple schools of fish were responsible for up to five hammerheads being spotted along the Port Kembla and Primbee coast.

Meanwhile, swimmers at Warilla beach were ordered out of the water after a shark - believed to be frequent visitor ‘‘Bruce’’ - was seen by lifeguards on Thursday.

Shellharbour City Council beach lifeguard supervisor Mitch Copas said the shark was spotted at the southern end of the beach, near Little Lake, about 11.45am. 

‘‘We can never be 100 per cent sure it’s the same shark, but [it had] very similar patterns in the water and a similar fin [to Bruce],’’ Mr Copas said.

‘‘It was probably a couple of hundred metres off shore, but close enough that they [lifeguards] could see it.

‘‘He is feeding, there is a big school of fish pretty much where he was.’’

Mr Copas said up to 30 people were swimming in Little Lake at the time and a similar number of swimmers were in the nearby flagged area. 

‘‘We closed the beach immediately and called everyone in,’’ he said.

‘‘We’ll be closed for the rest of the day [Thursday], the fish just keep coming in and out ... there’s a lot of action there.’’

At Gerroa, lifeguards and members of a surf school were put on alert after a small shark, possibly a bull shark, was spotted about 200 metres off shore.