The ABC's Vote Compass has revealed that 80 per cent of voters do not support the sale of agricultural land to foreign investors, but what happens when farmers want to sell and no Australians are interested in buying?

Jan and Merv Smith have worked their 230-acre family farm in Western Australia's Margaret River wine region for 44 years and are hoping to sell up and retire.

Their property has been on the market for two years and Ms Smith told 720 ABC Perth in that time the only interest they had had was from overseas investors.

"Mostly people from Asia — not just China, but other Asian countries as well — no Aussies at all have shown an interest," she said.

The farm has been in the Smith family for 63 years, first as a dairy farm then later switching to sheep for the wool market.

"My husband Merv and I took it over in 1972 and farmed with sheep for 25 years," she said.

"Then 20 years ago we decided to put grapes in when wool prices crashed."

The Smiths went on to start their own winemaking business, running a cellar door as well as offering tourist accommodation on the property.

'We might still be here at 80'

Their only son joined the business 11 years ago but decided it was too big to run on his own.

"My husband and I are now older than retirement age, we are close to 70," she said.

"We had a family get-together a couple of years ago and said, 'what are we going to do?'"

Jan and Merv Smith's property, where they run some sheep among the vines. ( Supplied: Jan Smith )

That was when the family decided to put the property on the market.

"If we are able to sell it to whoever we can, if there are no restrictions, we would definitely sell it," she said.

"If we don't sell it to them, we could be waiting another 10 or 15 years.

"We might be still here when we are 80."

Ms Smith said many of her farming neighbours faced the same situation.

"A lot of their kids have had a taste of life off the farm and when they come home they are not interested," she said.

Farm is our only super

If they cannot sell the farm, Ms Smith said they would rely on their staff for the day-to-day running and step back from the business.

"But we would prefer to sell if we can and move on and have a retired life that so many of our city friends in other businesses have been able to do," she said.

"This is our superannuation, we don't have anything else."

The Vote Compass report showed opposition to the sale of agricultural land to foreign buyers was strongest for voters in rural and regional areas, and for all voters aged over 55.

Foreign investors a minority

Anne Garnett, a senior economics lecturer at Murdoch University, said fears might be based on exaggerated ideas of foreign investment levels.

She said the most recent data showed that across Australia 12.4 per cent of agricultural land was fully foreign-owned; in Western Australia it is 7.3 per cent.

"Ninety-nine per cent of farm businesses in Australia are fully Australian-owned," she said.

Dr Garnett said foreign investment in agriculture could have huge benefits.

"The evidence shows that Australia has a huge demand for its food and fibre, because what we produce is of very high quality," she said.

"If we could get foreign investment to develop these industries it would really provide jobs and exports and greatly assist rural communities."