Professional Footballers Australia (PFA) is backing Maclaren and the organisation's president, Simon Colosimo, said: "Jamie sought to have his contract with the club terminated and the club isn't willing to do that.
"Perth have now filed a grievance and an arbitrator has been appointed. We're just waiting now to see if Perth is available for a directions meeting tomorrow. That would take place over the phone, in a conference call."
In the wake of Perth cheating the A-League salary cap and being barred from competing in the finals series by FFA as part of the club's penalty, Maclaren sought a release under the terms of the standard playing contract, citing a breach of the material, non-financial clause.
But the club has steadfastly refused to let him go, despite releasing senior players Danny Vukovic, Scott Jamieson and Youssouf Hersi. All three of those players were contracted beyond this season.
After being released late last month, Vukovic and Jamieson each spoke out against the club for not releasing Maclaren, saying the Perth players had been repeatedly told by the club that anyone who didn't want to remain could leave.
"There were numerous player meetings, collectively as a team and as individuals, where we were told by (Perth coach) Kenny Lowe that any player who was unhappy, the club won't stand in their way of leaving," Jamieson said then. "That was the message relayed many times.
"I was confused because the club was saying that, but now they're telling another player like Jamie Maclaren that they want to keep him and that they're not going to let him leave. I can't understand that.
"Jamie has been brilliant this year in keeping his head down and working hard, despite unluckily not starting many games. I know he was told on at least two occasions during the season he could leave at the end of the season, so now to be told he can't leave is very strange.
"I'm not too sure what the reasons are for this, but the boy clearly doesn't want to play for Perth anymore and it's come down to because he feels he's been lied to and they haven't looked after him.
"I do think it's unfair because he had one year left on his deal and he was told he could leave. Had he not been told stuff like that, well, then, it's a business."
Vukovic said: "I can't fathom why they aren't releasing him. We were in countless meetings with officials and coaching staff and Kenny told us numerous times if we weren't happy he wouldn't stand in our way. But that's exactly what's happening.
"He doesn't want to play for the club anymore and I understand why. Jamie's a very good young player and I'd hate to see something like this derail his momentum."
Maclaren, 21, was on the bench for most of the season at Perth behind imported striker Andy Keogh, but he started several games towards the end and finished with a flurry of goals.
Multiple A-League clubs are interested in signing Maclaren, who is a key member of the Australian under-23 side that is on the road to qualifying for the 2016 Olympic Games in Rio de Janeiro. There is also interest in Maclaren from overseas clubs.
Asked how quickly the matter might be resolved either way through arbitration, Colosimo said: "Obviously it's a pressing matter, so we're hoping it doesn't take too long, but that's entirely up to the arbitrator.
"The directions meeting results in some time-frames being set and then the parties involved will file their arguments for consideration.
"There's always still time to negotiate, but Perth has filed a grievance.
"We wouldn't have advised Jamie the way we did if we didn't believe he had the right to take the action he has taken."
