Lawyers Edmonton Oilers and Calgary Flames players are trying to have the NHL lockout declared illegal under Alberta law.
The NHL has argued before the Alberta Labour Relations Board that a league spanning two countries cannot operate under different laws for each team.
The labor board deferred a decision to a later date.
About a half-dozen players attended the hearing, including Oilers forward Sam Gagner, goalie Devan Dubnyk and veteran Ryan Smyth.
The lockout began last weekend and some players are already signing with European teams for the season. There have been no formal talks between the two sides since Sept. 12. Training camps were to have opened Friday. The league has already canceled preseason games through Sept. 30.
NHLPA lawyer Bob Blair told the panel that the two teams are Alberta businesses, so provincial labor laws must be followed.
"No one gets to choose what labor laws apply to them in this province," Blair said. "The law is the law is the law."
He said players from the Oilers and Flames never agreed to forgo their rights under the Alberta Labour Code.
"It applies to every employer and employee," he said. "That is the starting point."
NHL lawyer Peter Gall pointed out that 23 of the 30 teams are in the United States and work under the same rules because labor laws in the country are federally regulated.
"So all of the players on all of the teams have been included in one bargaining unit," Gall said. "The NHLPA has never bargained with individual teams. It has only bargained with the NHL."
Bill Daly, the league's deputy commissioner, told the panel there has never been individual bargaining between players and their teams. He said it's important all teams operate under the same rules.
Blair countered by saying the way the league and union operated in the past is irrelevant.
It's unclear what might follow if the board were to rule in favor of the NHLPA's request, but Daly said he couldn't imagine the fallout if that were to happen.
"It would be extremely destabilizing to how we do business and how we conduct this sports league," he said. "I don't know how we would proceed in the face of separate units in Alberta."
Last week, Montreal Canadiens players launched a similar case in Quebec. The labor board there turned down their request for a temporary injunction against the lockout, but also ruled that more hearings are needed to make a final decision on the application. No date for those hearings has been set.
The two sides remain far apart on key economic issues.
The NHL believes too much money is being paid in salaries and has proposed a system to address it. Its most recent offer called for the players' share in revenue to be set at 49 percent next season — down from 57 percent in the deal that expired last weekend — and proposed that it drops to 47 percent by the end of the six-year deal.
The union tabled an offer in which the salary cap would be set to fixed increases of 2 percent, 4 percent and 6 percent over the next three years. The system would then revert to a percentage-based system for the final two years.
"Everybody wants to play," Tampa Bay Lightning coach Guy Boucher said Friday night at the Toronto-Tampa Bay baseball game "Everybody wants to get going. There's goodwill on both sides. I'm sure they'll find a way, and hopefully it's quick. I have faith the players and owners, that they'll find a way. ... I'd be a liar to say that I'm not afraid. I'm staying very positive."