A St Heliers resident called the police after witnessing a group of around 10 people engaged in sexual activity in public at a central Auckland nudist beach.
Police say they received a report of a sexual incident in Ladies Bay, St Heliers, just after 6pm on Friday.
The resident and his fiancee went to Ladies Bay near their home for a swim after work around 5pm.
As he was collecting his towel after his swim, the man said he heard noises and saw a group of people having sex on the grass bank at the beach.
"It was so outrageous. So bizarre," said the man, who spoke to the Herald on the condition of anonymity.