The next day, a person defecated in the pool but Mrs Macaulay believed it was accidental.
"It was only a little bit and could have come out of a nappy."
On January 28, a person defecated a "large amount" in the deep end of the pool.
"I think the third one is deliberate because of where it was and purely by the amount ... it's annoying - there is no need for it."
After such an incident, the Dunedin City Council required the pool to be closed for 36 hours for a cleaning treatment.
The pool reopened on Monday and swimming lessons had resumed.
Security cameras at the pool were recording at the time of the latest incident and the footage was to be reviewed.
The person responsible would be trespassed from the pool but no further charges would be requested from police, she said.