Grain growers in the south-east coastal district of Western Australia were shocked by the sight of feral camels wandering through their crops.

The desert dwellers are rarely seen so far south, and are believed to be migrating away from dry conditions in the Nullarbor and Goldfields, in search of food and water.

But a biosecurity expert is blaming successive governments' poor management of Crown land for growing feral populations and the subsequent impacts on pastoralists and farmers.

Brett South said the feral camels ran through gates and fences. ( ABC Rural: Jon Daly )

Strange visitors

Brett South recently spotted a group of eight camels on a dirt road next to his farm in Beaumont, about 130 kilometres north-east of the coastal town of Esperance.

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"My grandfather-in-law has been farming out here for 20-odd years now and this is the first time he's seen camels," Mr South said.

"I was a bit blown away.

"I thought they might have been sheep or cattle."

Mr South said the herd ran through fences and gates.

"They wreck all your waterholes, they have no respect for your boundary fences and your gates," he said.

"The number of pests we have up here, we don't need to add camels to the list."

Camels are pests

WA is now home to the largest herd of feral camels in the world, with 45 per cent of the nation's camels, according to the Department of Biodiversity, Conservation and Attractions.

Because of the extensive damage they cause to pastoral infrastructure in WA, feral camels are declared pests in the state.

With that in mind, Mr South herded his mysterious mob of camels into a driveway and shot six of them, while two got away.

"These camels had walked a very long way to get water and feed," Mr South said.

"They were buggered and full of worms. They actually near on needed putting down."

Grain grower Aaron Pontifex quickly dispatched his uninvited guests. ( ABC Rural: Jon Daly )

Another herd of 10 feral camels were found on a farm in Mount Ridley, 100 km to the east of Beaumont.

Camel droppings alerted Ridley Downs farm manager Aaron Pontifex to his uninvited guests.

"I'd seen poo and I thought that was a bit unusual, so I went hunting for them and found them," Mr Pontifex said.

"They had smashed through a bit of the crop.

"I rang the boys ... went and got some guns and sorted them out."

Fleeing the Nullarbor

To the north of the Esperance grain-growing region are the arid regions of the Nullarbor and Goldfields.

Feral camels are a persistent issue for pastoralists in those areas, but they are not known to drift so far south.

Southern Hills Station is about 150 km north of the farms at Mount Ridley and Beaumont, and its owner Chris South sees up to 100 camels moving through his property each year.

But Mr South said low rainfall was beginning to drive those herds further south.

"We're certainly not in a drought, but we're in a below-average season," Mr South said.

"We've been in a below-average season for two years.

"We haven't had all of our dams full in one hit for about four-and-a-half years.

"If our water goes dry then the camels move out."

Feral camels roam more than 3.3 million square kilometres of outback Australia. ( Supplied: Ninti One )

Failure by governments

Between Southern Hills Station and the farmlands to the south are vast swathes of unmanaged Crown land and the Dundas Nature Reserve, which is 800,000 hectares of thick bushland.

Mr South said the migrating camels to the south likely originated from populations breeding on those big parcels of untenured land.

That land falls under the management of the Department of Biodiversity, Conservation and Attractions.

Mr South said he was not aware of any control programs underway in those areas.

"I don't believe the Conservation Department do many studies on what is there," he said.

"If there was some form of control, not just in the nature reserve, but in any Crown land, the pastoralists and the farmers wouldn't have the problems that we do because the camels wouldn't be moving in from other areas."

Ross Wood is a biosecurity expert and chief executive of the Goldfields Nullarbor Rangelands Biosecurity Association, which is the main organisation carrying out control programs on the camel populations in those arid regions.

"They're gradually infiltrating into the pastoral zone and we're spending more time and effort having to deal with them," he said.

Mr Wood said successive governments had failed to deal with the pest problems on Crown land.

"Their view has been that they can control the problem once it gets into different tenures like farming and pastoral land," he said.

"[It's] a ridiculous concept because it is so much harder to do once it is inside.

This map shows the distribution of feral camels in Australia in 2008. ( Sourced: Australia State of Environment Report 2016 )

"It's going to continue to happen unless we get good strong programs holding back camel populations in the desert."

A Department of Biodiversity, Conservation and Attractions spokesperson said camels were nomadic and travelled in small groups, making them hard to locate and control from the ground.

"Opportunistic shoot programs are carried out for the sparse population of camels in the Goldfields and South Coast regions," the spokesperson said.

"Camels are also removed through opportunistic shoot programs in the Dundas Nature Reserve and the surrounding area."

Control methods

Currently, it is estimated there are 1–1.2 million feral camels in Australia, and the population is growing by 8 per cent each year, according to the Centre for Invasive Species Solutions.

The last federally-funded control program was the $19 million Australian Federal Camel Management Project.

Between 2009 and 2013, 160,000 camels were culled in Central Australia using ground-based and aerial culling techniques.

But Mr Wood said that work had been undone by unchecked population growth on Crown land.

"This problem will just get worse and worse with weeds, camels, dogs and whatever other pests build up in the unmanaged Crown land, until there are control programs funded to deal with the problem where it lies," he said.

"Successive governments just keep ignoring the fact that they have a responsibility to manage the land that isn't managed by tenured operations."