The Saskatchewan Court of Appeal is hearing arguments about Bill 5, the province's essential services law that puts limits on how many public sector workers can go on strike.

The two combatants are the Saskatchewan Federation of Labour and the provincial government.

In February, Queen's Bench judge Dennis Ball found the law infringes on workers' rights and deemed it to be of "no force or effect." Ball gave the province a year to fix it.

However, the government is appealing parts of the decision.

In his decision, Ball upheld a second key piece of labour legislation passed by the Saskatchewan Party government and challenged by the unions — Bill 6.

That legislation amended the Trade Union Act, ending the practice of automatic union certification in cases where a majority of employees sign union cards.

Instead, a secret ballot vote is required to unionize a workplace.

The Trade Union Act amendments also raised the threshold percentage of workers needed to trigger a vote — to 45 per cent from 25 per cent.

The SFL said it will defend Ball's decision on essential services and will try to overturn his decision on union certification rules. Both pieces of legislation, passed in 2008, violate workers constitutional rights, according to the SFL.

2 court rooms filled

The Court of Appeal needed two court spaces to accommodate the intense interest in the case. One court room was reserved for some 20 lawyers making presentations to the panel of justices hearing the case. Another room, for news media and other interested people, watched the proceedings on television screens.

In his argument, one of the lawyers for the provincial government told the five justices that Ball went too far in his ruling.

"Simply put, Saskatchewan submits that it's not possible for this [appeal] court to uphold Justice Ball's decision as Canada's jurisprudence now stands," Graeme Mitchell said.

At one point, a lawyer for the Saskatchewan Federation of Labour was quizzed about the right to strike in Canada.

"I would say fundamentally it is a freedom that is restricted," Craig Bavis told the Court of Appeal. "There are certain obligations."

Saskatchewan's essential services law restricts the number of employees who can strike and applies where a strike could endanger life, health or safety, could cause damage or when a strike could disrupt the courts. The law covers thousands of public sector workers, from nurses and highway snow plow operators.

"I think that union workers aren't going to put their fellow citizens in danger of loss of life to exercise their right to strike," Bavis told the court panel.

A total of three days have been set aside for lawyers to make their presentations.

It was expected that no matter how the Court of Appeal determines the questions before it, the parties involved — if they are unsatisfied with the outcome — would seek leave to appeal to the Supreme Court of Canada.

With files from CBC's Sheryl Rennie