A rare albino kangaroo has been photographed on farmland in Western Australia's Great Southern region.

According to mammologist Mark Eldridge, principal research scientist at the Australian Museum, white or albino kangaroos occur once every 50,000 to 100,000 animals.

He said the fact that the image was captured in the wild made it even more unique.

"We do get reports of white kangaroos and white wallabies maybe once a year in various parts of Australia, so it does happen but it's certainly quite rare," he said.

Dr Eldridge said the genetic anomaly could be either albinism or an expression of white fur follicles.

"If they have the genes which prevent them from producing any pigment at all, then they would be albinos," he said

"But they may just have a mutation in the genes which produce the colour in their fur which makes them white, but they'd still have pigment in their eyes and nose and other places, so there could be two different things going on."

Sighting a first for farmers

For farmers Jeanette and Trevor De Landgrafft, who initially spotted the kangaroo near their farm south-east of Newdegate two months ago, it was a first.

"We were travelling home from town on a road that has paddock one side and reserve the other, and you're always looking out for kangaroos that time of day," Mr De Landgrafft said.

"And so we were going reasonably slow and a couple of roos jumped out in front, one larger one and a half-grown one, and the half-grown one was white.

"We stopped and got the phones out to get a picture, but they got away so we didn't have any evidence."

Mr De Landgrafft said luckily his wife had been with him in the car as he might not have believed his eyes.

He said despite living on farms in regional WA for more than 60 years, and having about 20km of property that neighboured reserve or national park, he had never seen a white kangaroo in the wild before.

"You see a lot of black rabbits and things like that that are different, but never a white kangaroo," he said.

Long wait for chance to capture image

Ms De Landgrafft said she had been waiting for the kangaroo to reappear again since April, and she finally got her chance last week.

"I happened to be coming back from a meeting and since we saw it a couple of months ago, I've been driving with my phone on camera when I go up and down," she said.

"And of course this time I didn't [have the phone on camera], so I was fluffing around trying to get my phone out and got it and reversed up and it sat there beautifully for me."

Mr De Landgrafft said since then he had heard several other people say they had seen the same animal.

Dr Eldridge said if the kangaroo mated with a fellow carrier of the white fur gene, the De Landgraffts could see more white mammals in their region in the future.

"Because it's a recessive gene, it would have to breed with a kangaroo that was also a carrier of the gene," he said.

"And they may occur at a frequency of one in a couple of hundred, so it would have to choose carefully."