Shark spotted at Auckland's Long Bay Beach

A shark has been spotted at Auckland's Long Bay Beach just days before Christmas, prompting members of the public to flee the water.

The shark was spotted by a member of the public at the popular Auckland beach at 3:30pm on Saturday.

Surf Life Saving Northern Region confirmed surf lifeguards closed the beach at 3:30pm for around 30 minutes before it was reopened when it was deemed safe to do so.

It's reported around 50 to 80 people were at the beach at the time of the shark sighting.

It's not known what type of shark was spotted.

It comes just days after a 21-year-old woman in Southland was bitten by a shark in a Riverton estuary, receiving a "significant laceration" to her leg.

She received a significant laceration to her leg that required treatment from emergency services.

It's believed the shark that bit the woman was a sevengill shark.