Osselton claimed that the workers were Wwoofers on a cultural and skill-based exchange, rather than employees, the inspectorate's investigation showed this was clearly not the case.
"It is not acceptable for businesses to attempt to evade their obligations by calling their workers volunteers and simply rewarding them with a bed and some food," Lumsden said.
The inspectorate was told food was routinely collected from waste bins at supermarkets and fed to workers, along with spoiled meat.
A worker told the ERA about "inhumane" living conditions, and sleeping in a small storage room under the stairs without proper ventilation or a heater.
The so-called "volunteers" worked up to 40 hours per week, performing tasks such as gardening or cutting firewood for Osselton's profit, Mbie said.
They were paid $120 a week in addition to food and accommodation - regardless of hours worked or what work they performed. A visitors book on site showed many workers were from overseas.
Two workers who both had worked for Robinwood Farms between November and December 2015 supported the account.
They said Osselton did not supply them with employment agreements, minimum wage or annual leave for their work. The ERA ruled they were each owed more than $2600.
Mbie said penalties to be paid by Robinwood Farms for the breaches were still being discussed, but the company could be liable for up to $20,000 per employee per breach.
"Wherever a worker is being rewarded in a business at whatever level, the Labour Inspectorate's starting position is that these people are employees and minimum employment standards apply."
On its Facebook page, Robinwood Wwoofing Farm is described as a "warm and comfortable home with an open fire which is lovely in the large lounge in the evenings, where you can relax or play and share some wine".
"The wonderful hosts will warmly welcome you in ten acres of land where you will meet the other travellers of the moment and also pigs, sheep, chickens, ducks, alpacas, Lavender the cow, Milo the goat, Ruck the crazy dog and the three cats."
It says people can stay as either Wwoofers or backpackers.
Robinwood Farms has been sought for comment.