One Nation MP David Farley has falsely claimed his electorate of Farrer produces 40 per cent of all Australia’s food.

An expert who has studied agriculture and the Murray-Darling Basin said Farley’s claim was “grossly overestimated”.

Sarah Wheeler, a water economics professor at Flinders University, said the real figure was around 6 per cent when calculated by gross value.

Farley is a former chief executive of the Australian Agricultural Company who became One Nation’s first elected MP in the House of Representatives when he won the Farrer byelection earlier this year. He made the claim during an interview on ABC TV’s Insiders program.

In the same interview, he also declared One Nation’s migration policy would include an extra 100,000 people a year, on top of the 130,000 it had already flagged – leaving a slightly higher total than under Labor. That detail prompted rebukes from party leader Pauline Hanson and Farley’s lower house colleague Barnaby Joyce.

“I’ve got the full support of the party to pursue what I’m doing, especially for Farrer,” Farley told host David Speers.

“Forty per cent of the nation’s food comes out of Farrer, so it’s pretty important.”

David Farley with his One Nation colleagues in Canberra. Photo: Mike Bowers

Farley has also previously used the 40 per cent figure about the Southern Basin, which consists of the southern half of the Murray-Darling Basin.

The basin is an agriculture-heavy region of south-eastern Australia that is around four times larger than Farrer.

“The Southern Basin produces around 40 per cent of Australia’s food,” Farley said in a June 28 Facebook video.

Farley did not respond when he was contacted to clarify his claims.

But, regardless of whether he is referring to his seat of Farrer or the Southern Basin, Farley’s claim is wrong.

The 40 per cent figure broadly matches the proportion of Australia’s agriculture produced in the whole of the Murray-Darling Basin, an area that includes most of NSW and Victoria and is around eight times larger than Farrer.

The Murray-Darling Basin covers just over one million square kilometres, according to the Bureau of Meteorology.

According to the Murray-Darling Basin Authority, it includes about 75 per cent of NSW, more than 50 per cent of Victoria, 15 per cent of Queensland, 8 per cent of South Australia and all of the Australian Capital Territory.

It also contains 40 per cent of all Australian farms, the authority says.

Farrer electorate, which sits entirely within the basin, covers around 126,000 square kilometres, according to the Australian Electoral Commission. That means it makes up around one-eighth of the basin.

Wheeler said the most recent reliable estimate of food production by local area came from the Australian Bureau of Statistics’ Agricultural Census 2021 data. It lists the gross value of agricultural output in certain statistical areas, including crops, fruit and nuts, vegetables, dairy, eggs and slaughtered livestock.

Wheeler said monetary value was the best way to estimate food products that were measured in different units, such as tonnes, litres and livestock numbers.

While the ABS data did not report agricultural output by electorate, an estimate for Farrer could be calculated by adding data from 48 smaller statistical areas (SA2s) that fell wholly or partly within Farley’s electorate, Wheeler said.

ABS defines SA2s as medium-sized geographic areas with a population between 3000 and 25,000 people.

Wheeler said her team estimated how much of each SA2 fell within the Farrer electorate, and assumed agriculture was distributed evenly across those border areas.

Based on that analysis, carried out exclusively for AAP FactCheck, Wheeler and her team estimated the gross value of agricultural production in Farrer was around $4.4 billion in 2021.

The gross value of all Australian agricultural production was $71 billion in the same year, meaning Farrer accounted for around 6.2 per cent of the total output.

Wheeler said that while her estimate had a likely margin of error of around 1-2 per cent, it was clear Farley was wrong.

“Overall, it’s safe to assume that the figure of 40 per cent of Australia’s food production value is grossly overestimated,” she said.

The ABS data shows the whole Murray-Darling Basin region produced $30 billion of agriculture in 2021, which is around 42 per cent of the Australian total.

The Murray-Darling Basin Authority also says around 40 per cent of Australia’s agricultural produce comes from the Basin, “including 100 per cent of our rice, 74 per cent of our grapes and 30 per cent of our dairy”.

-AAP