Donna McPherson supplied The Courier with photos of balls on the bay after visiting the beach earlier this week morning.
The Courier sent the images to the Ministry for Primary Industries (MPI) and their botanist conferred with Landcare Research in identifying the objects as seagrass balls. Ms McPherson said she visited the beach on Wednesday morning and had seen the "amazing sight".
"I walked halfway down the beach and saw about 100," she said.
"One I saw was about as big as a softball and the rest were a bit smaller than my hand."
Ms McPherson said she had never seen anything like them before. MPI acting manager surveillance and incursion investigation Mike Taylor said the structures were seagrass balls, also known as neptune balls or fibre balls.
"The ones in your pictures are likely from a land grass species [such as marram grass] washed into the sea by erosion and shaped into balls," he said.
The balls had been found before in Invercargill and posed no threat to security, he said. Ms McPherson said the balls looked and felt as if they were made from pine needles.
"There had been strong seas and a high sea the night before, and a very low tide," she said.
