Wendy Campion was walking her Jack Russell-cross dog when she spotted what she at first thought was a very large shaggy dog - about the size of a Saint Bernard - on the loose on Monday morning.
She then realised it was a big, hairy pig staring at them, and she took a photo.
"I went no, that is definitely a pig, rather large one. He just stood and stared at us for a little while and then the next minute he comes charging across quite quickly," she said.
Campion said as she was unsure how the pig or her 13-year-old dog would react, so she scooped her pet up and quickly moved on.
"He went at quite a rate of knots. I didn't realised pigs could move so fast," she said.
The pig was last seen continuing up the road towards the rugby fields.
Campion said she posted the photo of the pig to her local Facebook page because she emigrated from the United Kingdom to New Zealand only last year, and had recently moved to Pegasus, so she was not sure if it was a typical visitor.
"We're new to the country so we're not sure what goes on around here, but it is hilarious," she said.
The Facebook post had not resulted in any owner coming forward but people had suggested the town change its name to Pig-asus.
RNZ has contacted Waimakariri District Council see if staff have encountered the pig but it is yet to respond.
