A proposed dump in Western Australia's South West could spell the end for local numbat populations by drawing more feral predators, environmentalists say.

There are concerns the dump will attract more feral animals to the Dryandra Woodland, a natural habitat for the small endangered marsupial about 170 kilometres south-east of Perth.

There were 800 numbats in the Woodland area in the early 1990s, but only about 50 remain.

John Lawson of the volunteer Numbat Task Force said there are already feral animals in the Woodland, and the dump is likely to attract more.

"If the cat numbers built up, they would eventually spread out, and there are bush corridors that run between that proposed site and Dryandra Woodland," he said.

"Not just cats, but black rat, raven and fox."

The Dryandra Woodland is 28,000 hectares in size, comprising blocks that make up the Lol Gray, Highbury and Montague state forests.

The dump would be established on part of a parcel of land on Wandering-Narrogin Road.

It is several kilometres from Dryandra, but John Lawson said it was near enough.

"Is it worth the risk of putting something that could have serious impact on such a wonderful and precious bit of land that's left, and the animals in it?" he asked.

Feral animals will be controlled: EPA

But the Environmental Protection Authority (EPA) has decided not to formally assess the proposal, saying the site is up to 12 kilometres from the Dryandra Woodland central block conservation reserves, and a high fence is planned.

It said further management measures would be required to control the potential "indirect" impacts of feral animals.

If such conditions can not be imposed, the EPA said the facility should be in "a location that will reduce the potential environmental impacts to conservation significant terrestrial fauna".

Cuballing Shire Chief Executive Gary Sherry said the tip would be relatively small.

"This site at its greatest will handle about 7,000 tonnes per annum," he said.

"Compare that with other proposals in The Wheatbelt where the tonnages were upwards of 100,000 tonnes."

Mr Sherry said the seven shires involved would not want to harm native animals.

"The numbat is our shire logo, an emblem, so it is something that's very close to us," he said.

"The Shire of Cuballing and surrounding councils are keen to protect our remnant vegetation, our remnant wildlife."

He said the shire's existing dump is closer to Dryandra than the new one would be.

"Our site is only three kilometres from the Dryandra Woodland whereas this current proposal for a regional site is some seven kilometres from Dryandra Woodland," he said.

WA Greens MLC Lyn MacLaren is appealing against the EPA's decision.

"What the EPA should've done is assess the range that numbats will be living in and the impact of an increase in predators due to the waste dump," she said.

"They're extremely rare, if it weren't for the breeding programs that we have in place, I would think that they'd be extinct in the wild."