A British tourist says he was left gobsmacked after spying an unusually big cat while on a walk in the South Island.

Nick Baggott was walking around Lake Tekapo peninsula when he and partner, Juli Wood, spied the animal.

"It was probably about 100m to 150m away so we weren't right up next to it but it looked much bigger than a normal cat.

"I mean, we were looking at it to start with going 'what is that?'. We then realised it was very cat-like. To me it was like the size of a small lamb, so I would say two to three times bigger than I would expect a cat to be."

Baggott said they had got to the most northerly part of the walk, close to the lake, when the big cat walked across in front of them in the distance.

"We could see it loping across in front of us and I just got my camera out and pointed at it and got one shot but it didn't hang around.

"It wasn't racing but it made off fairly quickly. I'd say it saw us and didn't want to hang around where we were."

Baggott and Wood are on holiday from their Reading, London, home to spend Christmas with their daughter in Christchurch.

After their walk, he decided to google "big cats around Tekapo" and were surprised to see other sightings in the past.

"There had been some talk about big cats in Twizel which is where we're staying at the time.

"I was just amazed by it to be honest, I've not seen anything quite like that."

A supposed sighting of a "Canterbury black panther" was exposed as a hoax earlier this year.

Canterbury resident Sam Williamson contacted the Herald to say he had spotted what he believed was a large cat the size of "medium dog".

However, closer inspection of his claim has found that the image he provided appears to have come from Victoria, Australia, where locals in 2012 stumbled across the panther-like feline lurking in the Wombat State Forest.

There have been a number of alleged sightings of supposedly large cat-like animals around Mid Canterbury.

In 2013, a delivery driver spotted what he described as a large cat-like animal feeding on road kill just outside the Fairlie township in the early hours of the morning.

The description was remarkably similar to reports in a number of sightings of the panther-like animal in Mid Canterbury roughly the size of a Labrador dog, with a round head and distinctive long tail.

Sightings of the strange looking animal have gone back as far as 1992 when the animal was spotted at the Ashburton River mouth.