Sharks spotted in northern NSW

Two sharks have been spotted in northern NSW and a beach has been closed a day after a teenager was attacked in the area.

A dog was taken by a shark at a south Sydney beach on the weekend. (AAP) Source: AAP

A two-metre white shark has reportedly been sighted near Tweed Heads in northern NSW.

The shark was sighted by the NSW Department of Primary Industry's aerial team in northern Kingscliff on Tuesday morning and lifeguards were alerted, according to their shark smart social media alerting.

The sighting comes a day after 17-year-old Cooper Allen was bitten on the leg by a shark while surfing near Ballina, about 90km south of Kingscliff.

Lennox Head beach in the Ballina region remains closed after a three-metre great white shark was spotted earlier on Tuesday morning.