Labour Minister Don Morgan said the ruling broke new ground when it stated there is charter protection for the right to strike.
"A constitutional right to strike does not exist in Canada anywhere else so that part of the judgment is something that we want to appeal," Morgan said Monday at the legislature in Regina.
"The position that the judge took was that under the Charter of Rights and Freedoms, that people have a constitutional right to organize, to share information and there's a right to organize.
"Now he extended that to create a constitutional right to strike...and that's something we disagree with," Morgan added.
Morgan also said the lower court ruling could impact how legislation is drafted across Canada.
The essential services legislation was introduced in December 2007 shortly after the Saskatchewan Party won its first provincial election.
The legislation stated employers and unions had to agree on which workers were so needed they could not walk off the job. Unions were outraged, however, because the law also stated that if the two sides can't agree, employers can dictate who is essential.
The Saskatchewan Federation of Labour, representing about two dozen plaintiffs, challenged the law.
A Court of Queen's Bench judge ruled in February that the law goes too far because it infringes on the freedom of association of employees. Justice Dennis Ball said "no other essential services legislation in Canada comes close to prohibiting the right to strike as broadly, and as significantly."
But Ball upheld the principle of essential services and gave the government 12 months to fix the law.
The Service Employees International Union-West raised concerns Monday about the changes. Union president Barb Cape said both unionized and non-unionized workers need to have a more active role in the process.
Cape said there are a lot of people who still don't know how the changes would affect them.
"Young workers, marginalized workers just do not have the opportunity to participate in these labour changes, and they're going to be the folks most impacted by these, so ... our government needs to step back and really give them a chance to have their voice heard," she said.
Morgan said the changes will be part of new legislation introduced this fall when the government overhauls 15 separate pieces of workplace-related rules into one omnibus labour law.
"We want to have some direction from the court so we've got clarity as to the limits of how far essential services can or should go. Does it go just to things that are an immediate health crisis? Does it go to broader things like highways and the security of a building, for example, with the heating system or that type of thing?" he said.
"We're looking to the court for some clarity on that."
The appeal court has set aside three days to hear arguments.
(The Canadian Press, With files from CJWW)