The search is on for a quokka that inadvertently escaped Rottnest Island on a rubbish barge and is now believed lost in a Perth waste and recycling facility.

A staff member at the Regional Resource Recovery Centre in Canning Vale, in Perth's southern suburbs, spotted the distinctive small marsupial last week and took a photo, but did not realise it was a quokka.

It was not until they showed the image to a colleague that it was reported it to the Rottnest Island Authority.

Matt Swan, a wildlife officer with the Department of Parks and Wildlife (DPAW), told ABC Radio Perth that it was thought the quokka inadvertently made its way onto a barge taking refuse from the island to the mainland.

"There is a quokka population that hang around where people are [on Rottnest Island] and I guess they are a bit more friendly and a bit more inquisitive about waste and refuse," he said.

"Somehow this poor quokka has ended up on a rubbish barge."

Rottnest Island is 18 kilometres west of Fremantle and an A-class nature reserve where quokkas can live in a conservation habitat relatively untroubled by predators.

All waste is removed to the mainland for processing.

Would bakery treats bring you out of hiding?

Mr Swan said the challenge for staff was to find the quokka at the 12-hectare recycling site.

"Wildlife officers have attended the site and had a good look around," he said.

"There are large open skips right the way through to bushland.

"There are lots of habitat and hiding spots for a quokka to hang out.

"Actually trying to identify where it might be and whether it is still inside the facility is a bit hard."

Staff have toyed with the idea of buying some treats from a bakery and throwing them around to see if that brings the quokka out of hiding.

Rottnest Island is an A-class nature reserve and safe haven for quokkas. ( 720 ABC Perth: Emma Wynne )

The Rottnest Island Bakery is one of the island's most popular food venues and it could remind the quokka of home.

Mr Swan said anyone who spotted a quokka in the area should contact the wildlife hotline (06 9474 9055) immediately.

Quokka can never go home

"There is no doubt this would be stressful for the animal," Mr Swan said.

"It is a very different environment and there are different predators on the mainland, including cats and dogs."

The good news is that the quokka is unlikely go hungry.

"They are grazers by nature so green grass is really a staple part of their diet," Mr Swan said.

"I'm told the facility has enough grass there to sustain the quokka, but it is whether he is prepared to hang around or keeps moving on."

Sadly for the animal, even if it is found it will never be able to go home.

"We don't know what it has been exposed to here," Mr Swan said.

"Rottnest Island has such great conservation value that if we potentially put onto Rottnest Island something that it has been exposed to, we would potentially put all the quokkas in jeopardy."

There are around 10,000 quokkas on Rottnest Island and around 4,000 on the mainland.

Mainland quokka populations live in small groups of 50 to 150 in the Darling Ranges, east of Perth, and in small pockets of south-west Western Australia.