Lorna Kerse, of Auckland, was walking Billie, a huntaway-spaniel cross, about 8.45pm on Monday night when the deaf, duck-chasing dog got caught up about 40m offshore in buoys beyond the Roys Bay swimming pontoon.
Mrs Kerse said she could tell Billie was caught but did not feel confident entering the choppy and cold water to rescue her.
While she rang her father-in-law, Terry Kerse, for help, an English couple who were on the beach went and found Gus, who Mrs Kerse thought might be about 15.
"Gus just got in and swam to the pontoon, then dived in again and went and got her and released her. These days you hear so much about the youth of today, especially around New Year's Eve, and it is nice to have such a positive experience.
"He was just really lovely, even though I did panic he might end up caught himself," Mrs Kerse said.
She estimated the incident took about 15 minutes to resolve.
It proved quite an ordeal at the time for her elderly pet, who had suffered a stroke last year and cannot hear commands properly.
However, yesterday Billie was back to her normal inquisitive stuff and despite not really being a swimming dog, was still interested in ducks.
"Now she is none the worse for wear.
"She's saying come on, I've had a taste for it now. Let's have more," Mrs Kerse said.
Mrs Kerse felt she had not thanked Gus adequately on Monday because she was anxious to attend to Billie, who was "shivering and quivering, and a wreck".
She would like him to get in touch so she could thank him again and offer him an acknowledgement.
The Otago Daily Times Wanaka office (03 443-1307) can put Gus in touch with Mrs Kerse.
