The legend you are asking about is the Legend of Pania. A statue stands in honor of this legend outside the city of Napier in New Zealand. Below is a shortened version of Pania's story.
• Pania was once a beautiful mermaid, or maiden of the sea, who swam in ocean during the day and sat between the flax bushes near a stream at night. On one of those nights, the son of a Maori chief, the handsome Karitoki came to the stream for a drink.
• Pania became devoted to the young mean and after sitting a spying on him for a few nights, she cast a spell on him to make him fall in love with her. They got married in secret and went back to his hut in the village.
• Every morning before daybreak, Pania had to return to the ocean but she promised to come back to Karitoki every night. Karitoki however grew tired of missing his wife and being taunted from his fellow villagers. He went to see a wise village elder or a kaumatua. The kaumatua knew about sea maidens and she told Karitoki that if he got Pania to eat a small amount of food, she would not be able to return to the sea.
• Whilst she slept that night, Karitoki placed some food in Pania's mouth, thinking she would swallow it. But this was seen by Ruru the morepork (a New Zealand owl) and he called a loud warning which woke Pania. She was scared for her life and fled back to the ocean.
• Pania was never seen by Karitoki again.
The legend also states that sometimes, if you look down into the sea where the reef is, you will be able to see Pania stretching out her arms. It is unknown where she is reaching out for Karitoki or for her people to help her.
The sea off the shores of Napier is now guarded and protected by the spirit of Pania and Karitoki's son, Moremore. He disguises himself a as stingray, shark or octopus.
• Pania was once a beautiful mermaid, or maiden of the sea, who swam in ocean during the day and sat between the flax bushes near a stream at night. On one of those nights, the son of a Maori chief, the handsome Karitoki came to the stream for a drink.
• Pania became devoted to the young mean and after sitting a spying on him for a few nights, she cast a spell on him to make him fall in love with her. They got married in secret and went back to his hut in the village.
• Every morning before daybreak, Pania had to return to the ocean but she promised to come back to Karitoki every night. Karitoki however grew tired of missing his wife and being taunted from his fellow villagers. He went to see a wise village elder or a kaumatua. The kaumatua knew about sea maidens and she told Karitoki that if he got Pania to eat a small amount of food, she would not be able to return to the sea.
• Whilst she slept that night, Karitoki placed some food in Pania's mouth, thinking she would swallow it. But this was seen by Ruru the morepork (a New Zealand owl) and he called a loud warning which woke Pania. She was scared for her life and fled back to the ocean.
• Pania was never seen by Karitoki again.
The legend also states that sometimes, if you look down into the sea where the reef is, you will be able to see Pania stretching out her arms. It is unknown where she is reaching out for Karitoki or for her people to help her.
The sea off the shores of Napier is now guarded and protected by the spirit of Pania and Karitoki's son, Moremore. He disguises himself a as stingray, shark or octopus.