Key Points:

A 4m-long shark swimming offshore in Mount Maunganui's Shark Alley was spotted yesterday for the third time this month.

A member of the public called police after seeing the shark about 12.15pm.

But Mount police found no sign of the shark when they checked offshore from the Main Beach, near Moturiki Island.

Senior Sergeant Tania Kura said there was little officers could do so the Mount Maunganui Lifeguard Service was contacted. Mount Maunganui Lifeguard Service administrator Shelley Kerr said it was the third report lifeguards had received about a 4m to 4.5m shark swimming in the area in the past month.

"It sounds like the same one."

However, none of the sharks has been seen by lifeguards.

Sharks were commonly seen in the aptly-named area because they liked to eat the stingray and fish that frequented the spot, Ms Kerr said.

"It's not called Shark Alley for nothing. But they're usually well fed, so that's okay."

She said it was a timely reminder for swimmers to keep a watch for sharks at all times and to let other swimmers know if one was spotted.

Phoning the police would be of little help.

"I don't know what they were going to do - go out and arrest it maybe," she joked.

The shark sighting came less than 24 hours after Papamoa mothers Elaine Dixon and Anna Beck saw a fin and ran screaming to get their three-year-old daughters out of the water.

The shark was believed to be between 1.5m and 2m long. It was seen at Papamoa, near Hartford Ave, on Wednesday.