She lay in the sand near the penguin to take photographs and the penguin, which appeared to be in good health, came closer.
"It was really lovely. It came and sat next to me, then about 30 minutes later it lay down and went to sleep - it was less than 2ft (60cm) away."
The penguin seemed curious and friendly, she said.
"It was very exciting."
The bird was discovered by Robyn Mutch, who was on a walk along the beach near Goodwood when she noticed a penguin "pop out" of a large wave and walk up the beach, her husband Paul Mutch said.
A member of a local bird-watching group, he took note of its features and recognised it was not a blue or yellow-eyed penguin normally seen in the area.
"It just lay down in the sun. It didn't seem bothered by us - it was quite something."
Research, confirmed by the Department of Conservation, indicated it was a gentoo penguin.
Gentoos are considered "near threatened" as only 320,000 breeding pairs exist, mostly on the Antarctic Peninsula and sub-Antarctic islands.
They are identified by their reddish orange bill and the white patch around and behind the eye that joins on the crown.
The monogamous birds generally forage close to shore but have been known to occasionally end up on New Zealand, Australian and Argentinian beaches.
Mr Mutch said it appeared a gentoo had been spotted at Warrington about 40 years ago, only the fifth sighting in New Zealand since 1905.
The penguin left the beach the day it arrived.
