A keen horsewoman herself, Ms Sorrell said it was rare to have the opportunity to see that many horses galloping through the surf.
"I almost burst into tears, it was so spectacular," she said.
"I'm not sure if it was 18 or 20 [horses]; they were difficult to count," she said.
Yesterday's beach conditions were "wet and miserable", but it did not stop the shoot going ahead, she said.
Enterprise Dunedin director John Christie said the film shoot permits
had ''been organised from scratch'', in about a week. The New Zealand film crew were also planning on filming in other, unspecified, locations around Otago.
Enterprise Dunedin had helped pull together the required permits.
"It's a great opportunity for Dunedin to showcase its attractions," he said.
Mr Christie did not know where all the horses had come from.
Signs put up by the film company stated the beach was closed during filming, for safety reasons. The advertisement was understood to be for the Lloyds Banking Group, which has historically had a black horse logo.