Keir Vallance says the labour strife at Saskatoon Transit isn't likely to be resolved any time soon.

An adjunct professor at the University of Saskatchewan and an expert on labour law, Vallance said both sides seem to be firmly dug in.

"Both sides, certainly in their press releases and in the comments they've made publicly, seem to be pretty entrenched," he told CBC Radio's Saskatoon Morning. "It's difficult to see how to get past this, and difficult to see how it's going to be resolved."

Negotiations broke off earlier this week between the city and the Amalgamated Transit Union shortly after the union entered into a strike position this weekend. The union has been without a collective agreement for the past four years and were locked out by the city in 2014.

While wages remain an issue, the major sticking point seems to be the union's pension plan.

"On the face of it, it's the same kind of issue that we saw over the Canada Post dispute over the summer," he said. "It's potentially a move, and I say potentially, because both sides disagree on this, from a defined benefit pension plan to a defined target pension plan."

The union believes the city is moving towards a defined target pension plan, where the employer is able to reduce pension payouts if the value of the plan drops. A defined benefit guarantees workers receive the same payout once retired. The city denies it is doing this.

"Either way, there probably wouldn't be any immediate change to the pensions of transit workers," said Vallance. "The sticking point here is, from the union's perspective, that they view the changes to moving to a defined target plan where benefits might be affected in the future, for newer hires and younger workers."

Meanwhile, Vallance doubts that even bringing in a mediator would help, considering the apparent state of negotiations.

"It's difficult to see how a mediator could help with this particular issue," he said. "It is a technical issue that both sides do not agree on. How do you manoeuvre toward a compromise?"

Ultimately, the law professor said he wouldn't be surprised if the matter ends in a strike or lockout.

"In the public sector, the fight is more about public perception, public opinion," he said. "The union and the city are perhaps a bit reluctant to do something too drastic too quickly before they can gauge public opinion."

The union has said the earliest any job action will take place would be after a tribunal hearing on Friday.