The legal firm involved in a landmark federal court action on behalf of long-term casual workers has warned against overreach that fails to recognise businesses that have done the right thing by employees.

Big business is urging the Morrison government to change workplace laws after last week’s landmark ruling found some long-term casuals are entitled to paid leave.

Legal firm, Adero, based in Canberra represents a labor hire company employee, Matthew Peterson, in a class action.

Adero was an intervenor in the case against WorkPac involving the employment of Robert Rossato, a mine worker at two Queensland mines owned by Glencore. He had been employed as a casual employee, with a loading on rolling contracts over a three-and-a-half-year period.

The Federal Court last week found that because Mr Rossato’s employment was “regular, certain, continuing, constant and predictable” he was eligible to entitlements of a full-time employee.

Adero says the latest decision will assist its other class actions against labour hire providers in the mining industry.

But Adero says, outside of those claims, it has not filed proceedings affected by the precedent set in the Rossato case.

The firm is wary of any government move to legislate on the issue and says there needs to be a recognition that the case relates to specific business models.

“If legislative reform does come, it should be in a form that protects businesses who have engaged casuals genuinely and paid those casuals 25 per cent more than their permanent equivalents,” Adero spokesperson Kellie Pledger said in a statement to The New Daily.

“We are currently living in a very uncertain job market as a result of COVID-19. Now more than ever, employees will be afraid to speak up about their workplace rights.

Adero hopes that the Morrison government will do right by employees and hold labour hire providers and big business to account by making the necessary distinction.’’

Industrial Relations Minister Christian Porter said last week the government would consider joining a High Court appeal if one were to be launched, but would not take the matter to the court itself.

“Given the potential for this decision to further weaken the economy at a time when so many Australians have lost their jobs, it may also be necessary to consider legislative options,” Mr Porter said.

With many casual workers hailing the decision on social media, Mr Porter said talks would be held with unions and employers to try and find a resolution.

Adero claims the distinction that Mr Porter and industry groups are failing to make is between businesses who employ casual workers for the same few hours each week on “a genuine 25 percent casual loading”, and those labour hire providers who use casuals as a way to lower wage bills and reduce liabilities.

“By obtaining workers through this third-party model, labour hire employees receive up to 40 per cent less pay than staffers despite performing the same work under the same supervision on site – a great saving for big business, but at what cost to those employees?” Ms Pledger said.

“Employees engaged on systemic, long-form rosters, whose employment arrangements are anything but casual are entitled to be paid accordingly.”

Although the ruling does not apply to all casuals, employers maintain the result is “double dipping” and fear a flood of class actions could result in backpay claims of up to $8 billion.

“There are 2.6 million casuals in Australia and 1.6 million of them work regularly and have done so for at least six months,” Australian Industry  Group’s Stephen Smith told the ABC.

#This article has been updated to clarify Adero’s role as intervenor in the Rossato case.